1661351040 has 256 divisors, whose sum is σ = 5963328000. Its totient is φ = 437059584.

The previous prime is 1661351033. The next prime is 1661351143. The reversal of 1661351040 is 401531661.

1661351040 is a `hidden beast` number, since 1 + 6 + 613 + 5 + 1 + 0 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 1661350995 and 1661351013.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1364512 + ... + 1365728.

It is an arithmetic number, because the mean of its divisors is an integer number (23294250).

Almost surely, 2^1661351040 is an apocalyptic number.

1661351040 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 1661351040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2981664000).

1661351040 is an abundant number, since it is smaller than the sum of its proper divisors (4301976960).

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

1661351040 is a wasteful number, since it uses less digits than its factorization.

1661351040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1324 (or 1306 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 1661351040 is about 40759.6741890806. The cubic root of 1661351040 is about 1184.3692846149.

The spelling of 1661351040 in words is "one billion, six hundred sixty-one million, three hundred fifty-one thousand, forty".