2155031521 has 4 divisors (see below), whose sum is σ = 2160718000. Its totient is φ = 2149345044.

The previous prime is 2155031507. The next prime is 2155031561. The reversal of 2155031521 is 1251305512.

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 2155031521 - 2⁷ = 2155031393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2155031561) 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, 2842671 + ... + 2843428.

It is an arithmetic number, because the mean of its divisors is an integer number (540179500).

Almost surely, 2^2155031521 is an apocalyptic number.

It is an amenable number.

2155031521 is a deficient number, since it is larger than the sum of its proper divisors (5686479).

2155031521 is an equidigital number, since it uses as much as digits as its factorization.

2155031521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5686478.

The product of its (nonzero) digits is 1500, while the sum is 25.

The square root of 2155031521 is about 46422.3170576394. The cubic root of 2155031521 is about 1291.6689175921.

The spelling of 2155031521 in words is "two billion, one hundred fifty-five million, thirty-one thousand, five hundred twenty-one".