21399883 has 4 divisors (see below), whose sum is σ = 22137840. Its totient is φ = 20661928.

The previous prime is 21399839. The next prime is 21399901. The reversal of 21399883 is 38899312.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21399883 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21399803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 368935 + ... + 368992.

It is an arithmetic number, because the mean of its divisors is an integer number (5534460).

Almost surely, 2^21399883 is an apocalyptic number.

21399883 is a deficient number, since it is larger than the sum of its proper divisors (737957).

21399883 is an equidigital number, since it uses as much as digits as its factorization.

21399883 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 737956.

The product of its digits is 93312, while the sum is 43.

The square root of 21399883 is about 4626.0007565931. Note that the first 3 decimals coincide. The cubic root of 21399883 is about 277.6326038868.

The spelling of 21399883 in words is "twenty-one million, three hundred ninety-nine thousand, eight hundred eighty-three".