861692640 has 96 divisors (see below), whose sum is σ = 2760428160. Its totient is φ = 225882624.

The previous prime is 861692639. The next prime is 861692641. The reversal of 861692640 is 46296168.

It is an interprime number because it is at equal distance from previous prime (861692639) and next prime (861692641).

It is a tau number, because it is divible by the number of its divisors (96).

It is a junction number, because it is equal to n+sod(n) for n = 861692592 and 861692601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861692641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13107 + ... + 43533.

It is an arithmetic number, because the mean of its divisors is an integer number (28754460).

Almost surely, 2^861692640 is an apocalyptic number.

861692640 is a gapful number since it is divisible by the number (80) 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 861692640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1380214080).

861692640 is an abundant number, since it is smaller than the sum of its proper divisors (1898735520).

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

861692640 is a wasteful number, since it uses less digits than its factorization.

861692640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30504 (or 30496 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 42.

The square root of 861692640 is about 29354.6016835521. The cubic root of 861692640 is about 951.5920267773.

The spelling of 861692640 in words is "eight hundred sixty-one million, six hundred ninety-two thousand, six hundred forty".