20920769 has 4 divisors (see below), whose sum is σ = 20937300. Its totient is φ = 20904240.

The previous prime is 20920763. The next prime is 20920771. The reversal of 20920769 is 96702902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12159169 + 8761600 = 3487^2 + 2960^2 .

It is a cyclic number.

It is not a de Polignac number, because 20920769 - 2¹² = 20916673 is a prime.

It is a super-2 number, since 2×20920769² = 875357151102722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20920763) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6194 + ... + 8955.

It is an arithmetic number, because the mean of its divisors is an integer number (5234325).

Almost surely, 2^20920769 is an apocalyptic number.

It is an amenable number.

20920769 is a deficient number, since it is larger than the sum of its proper divisors (16531).

20920769 is a wasteful number, since it uses less digits than its factorization.

20920769 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16530.

The product of its (nonzero) digits is 13608, while the sum is 35.

The square root of 20920769 is about 4573.9227146947. The cubic root of 20920769 is about 275.5450084184.

The spelling of 20920769 in words is "twenty million, nine hundred twenty thousand, seven hundred sixty-nine".