20642693 has 4 divisors (see below), whose sum is σ = 21354540. Its totient is φ = 19930848.

The previous prime is 20642689. The next prime is 20642731. The reversal of 20642693 is 39624602.

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 10543009 + 10099684 = 3247^2 + 3178^2 .

It is a cyclic number.

It is not a de Polignac number, because 20642693 - 2² = 20642689 is a prime.

It is a super-2 number, since 2×20642693² = 852241548584498, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20642603) 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, 355880 + ... + 355937.

It is an arithmetic number, because the mean of its divisors is an integer number (5338635).

Almost surely, 2^20642693 is an apocalyptic number.

It is an amenable number.

20642693 is a deficient number, since it is larger than the sum of its proper divisors (711847).

20642693 is an equidigital number, since it uses as much as digits as its factorization.

20642693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 711846.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 20642693 is about 4543.4230487596. The cubic root of 20642693 is about 274.3187235379.

The spelling of 20642693 in words is "twenty million, six hundred forty-two thousand, six hundred ninety-three".