20865669 has 32 divisors (see below), whose sum is σ = 32569344. Its totient is φ = 11753280.

The previous prime is 20865653. The next prime is 20865671. The reversal of 20865669 is 96656802.

It is not a de Polignac number, because 20865669 - 2⁴ = 20865653 is a prime.

It is a super-2 number, since 2×20865669² = 870752285635122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20865669.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20865769) 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, 27712 + ... + 28454.

It is an arithmetic number, because the mean of its divisors is an integer number (1017792).

Almost surely, 2^20865669 is an apocalyptic number.

20865669 is the 2442-nd nonagonal number.

It is an amenable number.

20865669 is a deficient number, since it is larger than the sum of its proper divisors (11703675).

20865669 is a wasteful number, since it uses less digits than its factorization.

20865669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 817.

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 20865669 is about 4567.8954672803. The cubic root of 20865669 is about 275.3028905103.

The spelling of 20865669 in words is "twenty million, eight hundred sixty-five thousand, six hundred sixty-nine".