21506079 has 8 divisors (see below), whose sum is σ = 32771200. Its totient is φ = 12289176.

The previous prime is 21506059. The next prime is 21506083. The reversal of 21506079 is 97060512.

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

It is not a de Polignac number, because 21506079 - 2¹⁷ = 21375007 is a prime.

It is a super-2 number, since 2×21506079² = 925022867908482, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21506029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 512029 + ... + 512070.

It is an arithmetic number, because the mean of its divisors is an integer number (4096400).

Almost surely, 2^21506079 is an apocalyptic number.

21506079 is a deficient number, since it is larger than the sum of its proper divisors (11265121).

21506079 is a wasteful number, since it uses less digits than its factorization.

21506079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1024109.

The product of its (nonzero) digits is 3780, while the sum is 30.

The square root of 21506079 is about 4637.4647168469. The cubic root of 21506079 is about 278.0910929333.

The spelling of 21506079 in words is "twenty-one million, five hundred six thousand, seventy-nine".