20642807 has 4 divisors (see below), whose sum is σ = 21308736. Its totient is φ = 19976880.

The previous prime is 20642789. The next prime is 20642821. The reversal of 20642807 is 70824602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70824602 = 2 ⋅35412301.

It is a cyclic number.

It is not a de Polignac number, because 20642807 - 2²⁴ = 3865591 is a prime.

It is a super-2 number, since 2×20642807² = 852250961678498, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20642807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20642837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 332918 + ... + 332979.

It is an arithmetic number, because the mean of its divisors is an integer number (5327184).

Almost surely, 2^20642807 is an apocalyptic number.

20642807 is a deficient number, since it is larger than the sum of its proper divisors (665929).

20642807 is an equidigital number, since it uses as much as digits as its factorization.

20642807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665928.

The product of its (nonzero) digits is 5376, while the sum is 29.

The square root of 20642807 is about 4543.4355943493. The cubic root of 20642807 is about 274.3192285153.

The spelling of 20642807 in words is "twenty million, six hundred forty-two thousand, eight hundred seven".