21519730 has 16 divisors (see below), whose sum is σ = 39314880. Its totient is φ = 8479152.

The previous prime is 21519727. The next prime is 21519791. The reversal of 21519730 is 3791512.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15390 + ... + 16729.

It is an arithmetic number, because the mean of its divisors is an integer number (2457180).

Almost surely, 2^21519730 is an apocalyptic number.

21519730 is a deficient number, since it is larger than the sum of its proper divisors (17795150).

21519730 is a wasteful number, since it uses less digits than its factorization.

21519730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32193.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 21519730 is about 4638.9363004896. The cubic root of 21519730 is about 278.1499199991.

It can be divided in two parts, 2151 and 9730, that added together give a square (11881 = 109²).

The spelling of 21519730 in words is "twenty-one million, five hundred nineteen thousand, seven hundred thirty".