21513370 has 8 divisors (see below), whose sum is σ = 38724084. Its totient is φ = 8605344.

The previous prime is 21513361. The next prime is 21513383. The reversal of 21513370 is 7331512.

It can be written as a sum of positive squares in 2 ways, for example, as 20802721 + 710649 = 4561^2 + 843^2 .

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, 1075659 + ... + 1075678.

Almost surely, 2^21513370 is an apocalyptic number.

21513370 is a deficient number, since it is larger than the sum of its proper divisors (17210714).

21513370 is a wasteful number, since it uses less digits than its factorization.

21513370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2151344.

The product of its (nonzero) digits is 630, while the sum is 22.

The square root of 21513370 is about 4638.2507478574. The cubic root of 21513370 is about 278.1225155693.

Adding to 21513370 its reverse (7331512), we get a palindrome (28844882).

The spelling of 21513370 in words is "twenty-one million, five hundred thirteen thousand, three hundred seventy".