20820969 has 35 divisors (see below), whose sum is σ = 33818513. Its totient is φ = 12812904.

The previous prime is 20820967. The next prime is 20820977. The reversal of 20820969 is 96902802.

The square root of 20820969 is 4563.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 2 ways, for example, as 10323369 + 10497600 = 3213^2 + 3240^2 .

It is not a de Polignac number, because 20820969 - 2¹ = 20820967 is a prime.

It is a super-2 number, since 2×20820969² = 867025500197922, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (20820967) by changing a digit.

It is a polite number, since it can be written in 34 ways as a sum of consecutive naturals, for example, 1601607 + ... + 1601619.

Almost surely, 2^20820969 is an apocalyptic number.

20820969 is the 4563-rd square number.

20820969 is the 2282-nd centered octagonal number.

It is an amenable number.

20820969 is a deficient number, since it is larger than the sum of its proper divisors (12997544).

20820969 is an frugal number, since it uses more digits than its factorization.

20820969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70 (or 16 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The cubic root of 20820969 is about 275.1061584633.

Multiplying 20820969 by its sum of digits (36), we get a square (749554884 = 27378²).

The spelling of 20820969 in words is "twenty million, eight hundred twenty thousand, nine hundred sixty-nine".