21252919 has 2 divisors, whose sum is σ = 21252920. Its totient is φ = 21252918.

The previous prime is 21252899. The next prime is 21252953. The reversal of 21252919 is 91925212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21252919 - 2²¹ = 19155767 is a prime.

It is a super-2 number, since 2×21252919² = 903373132041122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21253919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10626459 + 10626460.

It is an arithmetic number, because the mean of its divisors is an integer number (10626460).

Almost surely, 2^21252919 is an apocalyptic number.

21252919 is a deficient number, since it is larger than the sum of its proper divisors (1).

21252919 is an equidigital number, since it uses as much as digits as its factorization.

21252919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 31.

The square root of 21252919 is about 4610.0888277776. The cubic root of 21252919 is about 276.9955948158.

The spelling of 21252919 in words is "twenty-one million, two hundred fifty-two thousand, nine hundred nineteen".