861990525 has 96 divisors (see below), whose sum is σ = 1829347200. Its totient is φ = 393292800.

The previous prime is 861990523. The next prime is 861990539. The reversal of 861990525 is 525099168.

861990525 is a `hidden beast` number, since 8 + 619 + 9 + 0 + 5 + 25 = 666.

It is not a de Polignac number, because 861990525 - 2¹ = 861990523 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861990523) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 122811 + ... + 129639.

It is an arithmetic number, because the mean of its divisors is an integer number (19055700).

Almost surely, 2^861990525 is an apocalyptic number.

861990525 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

861990525 is an abundant number, since it is smaller than the sum of its proper divisors (967356675).

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

861990525 is a wasteful number, since it uses less digits than its factorization.

861990525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6876 (or 6865 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 45.

The square root of 861990525 is about 29359.6751514726. The cubic root of 861990525 is about 951.7016684754.

The spelling of 861990525 in words is "eight hundred sixty-one million, nine hundred ninety thousand, five hundred twenty-five".