21273899 has 2 divisors, whose sum is σ = 21273900. Its totient is φ = 21273898.

The previous prime is 21273893. The next prime is 21273911. The reversal of 21273899 is 99837212.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21273899 - 2⁴ = 21273883 is a prime.

It is not a weakly prime, because it can be changed into another prime (21273893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10636949 + 10636950.

It is an arithmetic number, because the mean of its divisors is an integer number (10636950).

Almost surely, 2^21273899 is an apocalyptic number.

21273899 is a deficient number, since it is larger than the sum of its proper divisors (1).

21273899 is an equidigital number, since it uses as much as digits as its factorization.

21273899 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 41.

The square root of 21273899 is about 4612.3637107236. The cubic root of 21273899 is about 277.0867110272.

The spelling of 21273899 in words is "twenty-one million, two hundred seventy-three thousand, eight hundred ninety-nine".