21465161 has 2 divisors, whose sum is σ = 21465162. Its totient is φ = 21465160.

The previous prime is 21465149. The next prime is 21465173. The reversal of 21465161 is 16156412.

It is a balanced prime because it is at equal distance from previous prime (21465149) and next prime (21465173).

It can be written as a sum of positive squares in only one way, i.e., 20070400 + 1394761 = 4480^2 + 1181^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21465161 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21465161.

It is not a weakly prime, because it can be changed into another prime (21465121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10732580 + 10732581.

It is an arithmetic number, because the mean of its divisors is an integer number (10732581).

Almost surely, 2^21465161 is an apocalyptic number.

It is an amenable number.

21465161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21465161 is an equidigital number, since it uses as much as digits as its factorization.

21465161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 26.

The square root of 21465161 is about 4633.0509386364. The cubic root of 21465161 is about 277.9146132879.

The spelling of 21465161 in words is "twenty-one million, four hundred sixty-five thousand, one hundred sixty-one".