8661345921 has 12 divisors (see below), whose sum is σ = 12517689600. Its totient is φ = 5771066040.

The previous prime is 8661345919. The next prime is 8661345923. The reversal of 8661345921 is 1295431668.

8661345921 is a `hidden beast` number, since 8 + 6 + 613 + 4 + 5 + 9 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (8661345919) and next prime (8661345923).

It is not a de Polignac number, because 8661345921 - 2¹ = 8661345919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (8661345923) 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, 246321 + ... + 279278.

It is an arithmetic number, because the mean of its divisors is an integer number (1043140800).

Almost surely, 2^8661345921 is an apocalyptic number.

It is an amenable number.

8661345921 is a deficient number, since it is larger than the sum of its proper divisors (3856343679).

8661345921 is a wasteful number, since it uses less digits than its factorization.

8661345921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527436 (or 527433 counting only the distinct ones).

The product of its digits is 311040, while the sum is 45.

The square root of 8661345921 is about 93066.3522493495. The cubic root of 8661345921 is about 2053.6596079078.

The spelling of 8661345921 in words is "eight billion, six hundred sixty-one million, three hundred forty-five thousand, nine hundred twenty-one".