21274427 has 2 divisors, whose sum is σ = 21274428. Its totient is φ = 21274426.

The previous prime is 21274399. The next prime is 21274439. The reversal of 21274427 is 72447212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21274427 - 2¹⁸ = 21012283 is a prime.

It is equal to p_1346195 and since 21274427 and 1346195 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21274427.

It is not a weakly prime, because it can be changed into another prime (21274457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10637213 + 10637214.

It is an arithmetic number, because the mean of its divisors is an integer number (10637214).

Almost surely, 2^21274427 is an apocalyptic number.

21274427 is a deficient number, since it is larger than the sum of its proper divisors (1).

21274427 is an equidigital number, since it uses as much as digits as its factorization.

21274427 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6272, while the sum is 29.

The square root of 21274427 is about 4612.4209478321. The cubic root of 21274427 is about 277.0890033601.

The spelling of 21274427 in words is "twenty-one million, two hundred seventy-four thousand, four hundred twenty-seven".