13156021 has 2 divisors, whose sum is σ = 13156022. Its totient is φ = 13156020.

The previous prime is 13156019. The next prime is 13156027. The reversal of 13156021 is 12065131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11655396 + 1500625 = 3414^2 + 1225^2 .

It is a cyclic number.

It is not a de Polignac number, because 13156021 - 2¹ = 13156019 is a prime.

Together with 13156019, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 13156021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13156027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6578010 + 6578011.

It is an arithmetic number, because the mean of its divisors is an integer number (6578011).

Almost surely, 2^13156021 is an apocalyptic number.

It is an amenable number.

13156021 is a deficient number, since it is larger than the sum of its proper divisors (1).

13156021 is an equidigital number, since it uses as much as digits as its factorization.

13156021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 13156021 is about 3627.1229645547. The cubic root of 13156021 is about 236.0703910011.

The spelling of 13156021 in words is "thirteen million, one hundred fifty-six thousand, twenty-one".