21079247 has 8 divisors (see below), whose sum is σ = 25138176. Its totient is φ = 17282232.

The previous prime is 21079243. The next prime is 21079271. The reversal of 21079247 is 74297012.

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

It is a cyclic number.

It is not a de Polignac number, because 21079247 - 2² = 21079243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21079243) 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, 65303 + ... + 65624.

It is an arithmetic number, because the mean of its divisors is an integer number (3142272).

Almost surely, 2^21079247 is an apocalyptic number.

21079247 is a deficient number, since it is larger than the sum of its proper divisors (4058929).

21079247 is a wasteful number, since it uses less digits than its factorization.

21079247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130957.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 21079247 is about 4591.2141095793. The cubic root of 21079247 is about 276.2390240174.

The spelling of 21079247 in words is "twenty-one million, seventy-nine thousand, two hundred forty-seven".