8661255021 has 16 divisors (see below), whose sum is σ = 13023006400. Its totient is φ = 5687987184.

The previous prime is 8661255019. The next prime is 8661255037. The reversal of 8661255021 is 1205521668.

8661255021 is a `hidden beast` number, since 86 + 6 + 1 + 2 + 550 + 21 = 666.

It is not a de Polignac number, because 8661255021 - 2¹ = 8661255019 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 (8661255041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2392126 + ... + 2395743.

It is an arithmetic number, because the mean of its divisors is an integer number (813937900).

Almost surely, 2^8661255021 is an apocalyptic number.

It is an amenable number.

8661255021 is a deficient number, since it is larger than the sum of its proper divisors (4361751379).

8661255021 is a wasteful number, since it uses less digits than its factorization.

8661255021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4787945 (or 4787939 counting only the distinct ones).

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

The square root of 8661255021 is about 93065.8638868194. The cubic root of 8661255021 is about 2053.6524235621.

Adding to 8661255021 its reverse (1205521668), we get a palindrome (9866776689).

The spelling of 8661255021 in words is "eight billion, six hundred sixty-one million, two hundred fifty-five thousand, twenty-one".