855990621 has 6 divisors (see below), whose sum is σ = 1236430910. Its totient is φ = 570660408.

The previous prime is 855990617. The next prime is 855990673. The reversal of 855990621 is 126099558.

855990621 is a `hidden beast` number, since 8 + 559 + 90 + 6 + 2 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 800324100 + 55666521 = 28290^2 + 7461^2 .

It is not a de Polignac number, because 855990621 - 2² = 855990617 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (855990521) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 47555026 + ... + 47555043.

Almost surely, 2^855990621 is an apocalyptic number.

It is an amenable number.

855990621 is a deficient number, since it is larger than the sum of its proper divisors (380440289).

855990621 is a wasteful number, since it uses less digits than its factorization.

855990621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95110075 (or 95110072 counting only the distinct ones).

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

The square root of 855990621 is about 29257.3173924063. The cubic root of 855990621 is about 949.4884119022.

The spelling of 855990621 in words is "eight hundred fifty-five million, nine hundred ninety thousand, six hundred twenty-one".