1913642640 has 240 divisors, whose sum is σ = 7909993728. Its totient is φ = 403743744.

The previous prime is 1913642609. The next prime is 1913642641. The reversal of 1913642640 is 462463191.

1913642640 is a `hidden beast` number, since 1 + 9 + 1 + 3 + 6 + 4 + 2 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1913642595 and 1913642604.

It is not an unprimeable number, because it can be changed into a prime (1913642641) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 50917 + ... + 80123.

Almost surely, 2^1913642640 is an apocalyptic number.

1913642640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1913642640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3954996864).

1913642640 is an abundant number, since it is smaller than the sum of its proper divisors (5996351088).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1913642640 is a wasteful number, since it uses less digits than its factorization.

1913642640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29246 (or 29237 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 1913642640 is about 43745.2013368324. The cubic root of 1913642640 is about 1241.5196941685.

It can be divided in two parts, 19136 and 42640, that added together give a triangular number (61776 = T₃₅₁).

The spelling of 1913642640 in words is "one billion, nine hundred thirteen million, six hundred forty-two thousand, six hundred forty".