20642765 has 16 divisors (see below), whose sum is σ = 29102976. Its totient is φ = 13857600.

The previous prime is 20642731. The next prime is 20642773. The reversal of 20642765 is 56724602.

It is not a de Polignac number, because 20642765 - 2⁸ = 20642509 is a prime.

It is a super-2 number, since 2×20642765² = 852247493690450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13721 + ... + 15150.

It is an arithmetic number, because the mean of its divisors is an integer number (1818936).

Almost surely, 2^20642765 is an apocalyptic number.

It is an amenable number.

20642765 is a deficient number, since it is larger than the sum of its proper divisors (8460211).

20642765 is a wasteful number, since it uses less digits than its factorization.

20642765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28900.

The product of its (nonzero) digits is 20160, while the sum is 32.

The square root of 20642765 is about 4543.4309722940. The cubic root of 20642765 is about 274.3190424712.

The spelling of 20642765 in words is "twenty million, six hundred forty-two thousand, seven hundred sixty-five".