21968497 has 8 divisors (see below), whose sum is σ = 22579200. Its totient is φ = 21361440.

The previous prime is 21968489. The next prime is 21968509. The reversal of 21968497 is 79486912.

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 21968497 - 2³ = 21968489 is a prime.

It is a super-2 number, since 2×21968497² = 965229720878018, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21968477) 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, 15004 + ... + 16402.

It is an arithmetic number, because the mean of its divisors is an integer number (2822400).

Almost surely, 2^21968497 is an apocalyptic number.

It is an amenable number.

21968497 is a deficient number, since it is larger than the sum of its proper divisors (610703).

21968497 is a wasteful number, since it uses less digits than its factorization.

21968497 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1823.

The product of its digits is 217728, while the sum is 46.

The square root of 21968497 is about 4687.0563256697. The cubic root of 21968497 is about 280.0701227432.

The spelling of 21968497 in words is "twenty-one million, nine hundred sixty-eight thousand, four hundred ninety-seven".