1986992640 has 640 divisors, whose sum is σ = 7954848000. Its totient is φ = 467140608.

The previous prime is 1986992639. The next prime is 1986992641. The reversal of 1986992640 is 462996891.

It is an interprime number because it is at equal distance from previous prime (1986992639) and next prime (1986992641).

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (1986992641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 22325716 + ... + 22325804.

It is an arithmetic number, because the mean of its divisors is an integer number (12429450).

Almost surely, 2^1986992640 is an apocalyptic number.

1986992640 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 1986992640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3977424000).

1986992640 is an abundant number, since it is smaller than the sum of its proper divisors (5967855360).

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

1986992640 is a wasteful number, since it uses less digits than its factorization.

1986992640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157 (or 135 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 54.

The square root of 1986992640 is about 44575.6956199227. The cubic root of 1986992640 is about 1257.1837326339.

The spelling of 1986992640 in words is "one billion, nine hundred eighty-six million, nine hundred ninety-two thousand, six hundred forty".