20990511 has 24 divisors (see below), whose sum is σ = 31135104. Its totient is φ = 13623120.

The previous prime is 20990479. The next prime is 20990521. The reversal of 20990511 is 11509902.

It is a happy number.

It is not a de Polignac number, because 20990511 - 2⁵ = 20990479 is a prime.

It is a super-2 number, since 2×20990511² = 881203104082242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20990521) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 68220 + ... + 68526.

It is an arithmetic number, because the mean of its divisors is an integer number (1297296).

Almost surely, 2^20990511 is an apocalyptic number.

20990511 is a deficient number, since it is larger than the sum of its proper divisors (10144593).

20990511 is a wasteful number, since it uses less digits than its factorization.

20990511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491 (or 488 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 20990511 is about 4581.5402431933. The cubic root of 20990511 is about 275.8508567244.

The spelling of 20990511 in words is "twenty million, nine hundred ninety thousand, five hundred eleven".