21164057 has 2 divisors, whose sum is σ = 21164058. Its totient is φ = 21164056.

The previous prime is 21164051. The next prime is 21164063. The reversal of 21164057 is 75046112.

It is a balanced prime because it is at equal distance from previous prime (21164051) and next prime (21164063).

It can be written as a sum of positive squares in only one way, i.e., 19678096 + 1485961 = 4436^2 + 1219^2 .

It is a cyclic number.

It is not a de Polignac number, because 21164057 - 2⁶ = 21163993 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21164051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10582028 + 10582029.

It is an arithmetic number, because the mean of its divisors is an integer number (10582029).

Almost surely, 2^21164057 is an apocalyptic number.

It is an amenable number.

21164057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21164057 is an equidigital number, since it uses as much as digits as its factorization.

21164057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21164057 is about 4600.4409571257. The cubic root of 21164057 is about 276.6090005780.

The spelling of 21164057 in words is "twenty-one million, one hundred sixty-four thousand, fifty-seven".