21342872 has 8 divisors (see below), whose sum is σ = 40017900. Its totient is φ = 10671432.

The previous prime is 21342857. The next prime is 21342883. The reversal of 21342872 is 27824312.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 1333922 + ... + 1333937.

Almost surely, 2^21342872 is an apocalyptic number.

It is an amenable number.

21342872 is a deficient number, since it is larger than the sum of its proper divisors (18675028).

21342872 is a wasteful number, since it uses less digits than its factorization.

21342872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2667865 (or 2667861 counting only the distinct ones).

The product of its digits is 5376, while the sum is 29.

The square root of 21342872 is about 4619.8346290749. The cubic root of 21342872 is about 277.3858394690.

The spelling of 21342872 in words is "twenty-one million, three hundred forty-two thousand, eight hundred seventy-two".