20990697 has 32 divisors (see below), whose sum is σ = 35954688. Its totient is φ = 10587456.

The previous prime is 20990677. The next prime is 20990707. The reversal of 20990697 is 79609902.

It is not a de Polignac number, because 20990697 - 2¹² = 20986601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20990657) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4608 + ... + 7950.

It is an arithmetic number, because the mean of its divisors is an integer number (1123584).

Almost surely, 2^20990697 is an apocalyptic number.

It is an amenable number.

20990697 is a deficient number, since it is larger than the sum of its proper divisors (14963991).

20990697 is a wasteful number, since it uses less digits than its factorization.

20990697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3389.

The product of its (nonzero) digits is 61236, while the sum is 42.

The square root of 20990697 is about 4581.5605419988. The cubic root of 20990697 is about 275.8516715070.

The spelling of 20990697 in words is "twenty million, nine hundred ninety thousand, six hundred ninety-seven".