21274237 has 2 divisors, whose sum is σ = 21274238. Its totient is φ = 21274236.

The previous prime is 21274219. The next prime is 21274247. The reversal of 21274237 is 73247212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13623481 + 7650756 = 3691^2 + 2766^2 .

It is a cyclic number.

It is not a de Polignac number, because 21274237 - 2⁷ = 21274109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21274247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10637118 + 10637119.

It is an arithmetic number, because the mean of its divisors is an integer number (10637119).

Almost surely, 2^21274237 is an apocalyptic number.

It is an amenable number.

21274237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21274237 is an equidigital number, since it uses as much as digits as its factorization.

21274237 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4704, while the sum is 28.

The square root of 21274237 is about 4612.4003512271. The cubic root of 21274237 is about 277.0881784719.

The spelling of 21274237 in words is "twenty-one million, two hundred seventy-four thousand, two hundred thirty-seven".