21395161 has 2 divisors, whose sum is σ = 21395162. Its totient is φ = 21395160.

The previous prime is 21395147. The next prime is 21395167. The reversal of 21395161 is 16159312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20985561 + 409600 = 4581^2 + 640^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21395161 is a prime.

It is not a weakly prime, because it can be changed into another prime (21395167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10697580 + 10697581.

It is an arithmetic number, because the mean of its divisors is an integer number (10697581).

Almost surely, 2^21395161 is an apocalyptic number.

It is an amenable number.

21395161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21395161 is an equidigital number, since it uses as much as digits as its factorization.

21395161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1620, while the sum is 28.

The square root of 21395161 is about 4625.4903523843. The cubic root of 21395161 is about 277.6121820057.

The spelling of 21395161 in words is "twenty-one million, three hundred ninety-five thousand, one hundred sixty-one".