21253937 has 2 divisors, whose sum is σ = 21253938. Its totient is φ = 21253936.

The previous prime is 21253931. The next prime is 21253943. The reversal of 21253937 is 73935212.

It is a balanced prime because it is at equal distance from previous prime (21253931) and next prime (21253943).

It can be written as a sum of positive squares in only one way, i.e., 21196816 + 57121 = 4604^2 + 239^2 .

It is a cyclic number.

It is not a de Polignac number, because 21253937 - 2¹² = 21249841 is a prime.

It is not a weakly prime, because it can be changed into another prime (21253931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626968 + 10626969.

It is an arithmetic number, because the mean of its divisors is an integer number (10626969).

Almost surely, 2^21253937 is an apocalyptic number.

It is an amenable number.

21253937 is a deficient number, since it is larger than the sum of its proper divisors (1).

21253937 is an equidigital number, since it uses as much as digits as its factorization.

21253937 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11340, while the sum is 32.

The square root of 21253937 is about 4610.1992364756. The cubic root of 21253937 is about 277.0000173772. Note that the first 4 decimals are identical.

The spelling of 21253937 in words is "twenty-one million, two hundred fifty-three thousand, nine hundred thirty-seven".