861551064 has 48 divisors (see below), whose sum is σ = 2545494120. Its totient is φ = 261075840.

The previous prime is 861551059. The next prime is 861551069. The reversal of 861551064 is 460155168.

861551064 is a `hidden beast` number, since 86 + 1 + 5 + 510 + 64 = 666.

It is an interprime number because it is at equal distance from previous prime (861551059) and next prime (861551069).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861551069) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 543117 + ... + 544700.

Almost surely, 2^861551064 is an apocalyptic number.

It is an amenable number.

861551064 is an abundant number, since it is smaller than the sum of its proper divisors (1683943056).

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

861551064 is a wasteful number, since it uses less digits than its factorization.

861551064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1087840 (or 1087833 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 36.

The square root of 861551064 is about 29352.1901056804. The cubic root of 861551064 is about 951.5399084366.

The spelling of 861551064 in words is "eight hundred sixty-one million, five hundred fifty-one thousand, sixty-four".