21184951 has 2 divisors, whose sum is σ = 21184952. Its totient is φ = 21184950.

The previous prime is 21184903. The next prime is 21184967. The reversal of 21184951 is 15948112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21184951 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21184151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10592475 + 10592476.

It is an arithmetic number, because the mean of its divisors is an integer number (10592476).

Almost surely, 2^21184951 is an apocalyptic number.

21184951 is a deficient number, since it is larger than the sum of its proper divisors (1).

21184951 is an equidigital number, since it uses as much as digits as its factorization.

21184951 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 31.

The square root of 21184951 is about 4602.7112661995. The cubic root of 21184951 is about 276.6999971135.

The spelling of 21184951 in words is "twenty-one million, one hundred eighty-four thousand, nine hundred fifty-one".