4521656021 has 4 divisors (see below), whose sum is σ = 4528276992. Its totient is φ = 4515035052.

The previous prime is 4521656011. The next prime is 4521656033. The reversal of 4521656021 is 1206561254.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 4521656021 - 2²⁶ = 4454547157 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 (4521656011) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3309461 + ... + 3310826.

It is an arithmetic number, because the mean of its divisors is an integer number (1132069248).

Almost surely, 2^4521656021 is an apocalyptic number.

It is an amenable number.

4521656021 is a deficient number, since it is larger than the sum of its proper divisors (6620971).

4521656021 is an equidigital number, since it uses as much as digits as its factorization.

4521656021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6620970.

The product of its (nonzero) digits is 14400, while the sum is 32.

The square root of 4521656021 is about 67243.2600414346. The cubic root of 4521656021 is about 1653.6077801599.

The spelling of 4521656021 in words is "four billion, five hundred twenty-one million, six hundred fifty-six thousand, twenty-one".