20990597 has 8 divisors (see below), whose sum is σ = 22645656. Its totient is φ = 19382272.

The previous prime is 20990591. The next prime is 20990603. The reversal of 20990597 is 79509902.

It is an interprime number because it is at equal distance from previous prime (20990591) and next prime (20990603).

It can be written as a sum of positive squares in 4 ways, for example, as 3568321 + 17422276 = 1889^2 + 4174^2 .

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 20990597 - 2²² = 16796293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20990591) 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, 10748 + ... + 12549.

It is an arithmetic number, because the mean of its divisors is an integer number (2830707).

Almost surely, 2^20990597 is an apocalyptic number.

It is an amenable number.

20990597 is a deficient number, since it is larger than the sum of its proper divisors (1655059).

20990597 is a wasteful number, since it uses less digits than its factorization.

20990597 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23367.

The product of its (nonzero) digits is 51030, while the sum is 41.

The square root of 20990597 is about 4581.5496286737. The cubic root of 20990597 is about 275.8512334525.

The spelling of 20990597 in words is "twenty million, nine hundred ninety thousand, five hundred ninety-seven".