21497079 has 8 divisors (see below), whose sum is σ = 29362032. Its totient is φ = 13981760.

The previous prime is 21497057. The next prime is 21497087. The reversal of 21497079 is 97079412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21497079 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21497009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87264 + ... + 87509.

It is an arithmetic number, because the mean of its divisors is an integer number (3670254).

Almost surely, 2^21497079 is an apocalyptic number.

21497079 is a deficient number, since it is larger than the sum of its proper divisors (7864953).

21497079 is a wasteful number, since it uses less digits than its factorization.

21497079 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174817.

The product of its (nonzero) digits is 31752, while the sum is 39.

The square root of 21497079 is about 4636.4942575183. The cubic root of 21497079 is about 278.0522950807.

The spelling of 21497079 in words is "twenty-one million, four hundred ninety-seven thousand, seventy-nine".