21914251 has 2 divisors, whose sum is σ = 21914252. Its totient is φ = 21914250.

The previous prime is 21914197. The next prime is 21914257. The reversal of 21914251 is 15241912.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21914251 - 2⁹ = 21913739 is a prime.

It is not a weakly prime, because it can be changed into another prime (21914257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10957125 + 10957126.

It is an arithmetic number, because the mean of its divisors is an integer number (10957126).

Almost surely, 2^21914251 is an apocalyptic number.

21914251 is a deficient number, since it is larger than the sum of its proper divisors (1).

21914251 is an equidigital number, since it uses as much as digits as its factorization.

21914251 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 25.

The square root of 21914251 is about 4681.2659612545. The cubic root of 21914251 is about 279.8394104651.

The spelling of 21914251 in words is "twenty-one million, nine hundred fourteen thousand, two hundred fifty-one".