656021121551 has 8 divisors (see below), whose sum is σ = 661633844784. Its totient is φ = 650417564160.

The previous prime is 656021121479. The next prime is 656021121577. The reversal of 656021121551 is 155121120656.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 656021121551 - 2³⁰ = 654947379727 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 (656021121851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2147666 + ... + 2434031.

It is an arithmetic number, because the mean of its divisors is an integer number (82704230598).

Almost surely, 2^656021121551 is an apocalyptic number.

656021121551 is a deficient number, since it is larger than the sum of its proper divisors (5612723233).

656021121551 is a wasteful number, since it uses less digits than its factorization.

656021121551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4582921.

The product of its (nonzero) digits is 18000, while the sum is 35.

The spelling of 656021121551 in words is "six hundred fifty-six billion, twenty-one million, one hundred twenty-one thousand, five hundred fifty-one".