20675665 has 16 divisors (see below), whose sum is σ = 25502400. Its totient is φ = 16085952.

The previous prime is 20675663. The next prime is 20675693. The reversal of 20675665 is 56657602.

20675665 is a nontrivial binomial coefficient, being equal to C(6431, 2).

It is a cyclic number.

It is not a de Polignac number, because 20675665 - 2¹ = 20675663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20675663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31834 + ... + 32476.

It is an arithmetic number, because the mean of its divisors is an integer number (1593900).

Almost surely, 2^20675665 is an apocalyptic number.

20675665 is the 6430-th triangular number.

20675665 is the 2144-th centered nonagonal number.

It is an amenable number.

20675665 is a deficient number, since it is larger than the sum of its proper divisors (4826735).

20675665 is a wasteful number, since it uses less digits than its factorization.

20675665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816.

The product of its (nonzero) digits is 75600, while the sum is 37.

The square root of 20675665 is about 4547.0501426749. The cubic root of 20675665 is about 274.4646997361.

The spelling of 20675665 in words is "twenty million, six hundred seventy-five thousand, six hundred sixty-five".