21313730 has 8 divisors (see below), whose sum is σ = 38364732. Its totient is φ = 8525488.

The previous prime is 21313729. The next prime is 21313741. The reversal of 21313730 is 3731312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 20259001 + 1054729 = 4501^2 + 1027^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1065677 + ... + 1065696.

Almost surely, 2^21313730 is an apocalyptic number.

21313730 is a deficient number, since it is larger than the sum of its proper divisors (17051002).

21313730 is a wasteful number, since it uses less digits than its factorization.

21313730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2131380.

The product of its (nonzero) digits is 378, while the sum is 20.

The square root of 21313730 is about 4616.6795427017. The cubic root of 21313730 is about 277.2595325051.

The spelling of 21313730 in words is "twenty-one million, three hundred thirteen thousand, seven hundred thirty".