21320715 has 32 divisors (see below), whose sum is σ = 37933056. Its totient is φ = 10154880.

The previous prime is 21320683. The next prime is 21320743. The reversal of 21320715 is 51702312.

It is not a de Polignac number, because 21320715 - 2⁵ = 21320683 is a prime.

It is a super-2 number, since 2×21320715² = 909145776222450, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21320691 and 21320700.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4282 + ... + 7808.

It is an arithmetic number, because the mean of its divisors is an integer number (1185408).

Almost surely, 2^21320715 is an apocalyptic number.

21320715 is a deficient number, since it is larger than the sum of its proper divisors (16612341).

21320715 is a wasteful number, since it uses less digits than its factorization.

21320715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3579.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21320715 is about 4617.4359768166. The cubic root of 21320715 is about 277.2898173076.

The spelling of 21320715 in words is "twenty-one million, three hundred twenty thousand, seven hundred fifteen".