861500421 has 16 divisors (see below), whose sum is σ = 1281160320. Its totient is φ = 572145120.

The previous prime is 861500411. The next prime is 861500461. The reversal of 861500421 is 124005168.

861500421 is a `hidden beast` number, since 8 + 615 + 0 + 0 + 42 + 1 = 666.

It is not a de Polignac number, because 861500421 - 2⁵ = 861500389 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861500411) 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, 53560 + ... + 67761.

It is an arithmetic number, because the mean of its divisors is an integer number (80072520).

Almost surely, 2^861500421 is an apocalyptic number.

It is an amenable number.

861500421 is a deficient number, since it is larger than the sum of its proper divisors (419659899).

861500421 is a wasteful number, since it uses less digits than its factorization.

861500421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121593 (or 121587 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 861500421 is about 29351.3274146162. The cubic root of 861500421 is about 951.5212638541.

Adding to 861500421 its reverse (124005168), we get a palindrome (985505589).

The spelling of 861500421 in words is "eight hundred sixty-one million, five hundred thousand, four hundred twenty-one".