20646813 has 8 divisors (see below), whose sum is σ = 30031776. Its totient is φ = 12513200.

The previous prime is 20646799. The next prime is 20646817. The reversal of 20646813 is 31864602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20646813 - 2⁴ = 20646797 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20646817) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 312798 + ... + 312863.

It is an arithmetic number, because the mean of its divisors is an integer number (3753972).

Almost surely, 2^20646813 is an apocalyptic number.

It is an amenable number.

20646813 is a deficient number, since it is larger than the sum of its proper divisors (9384963).

20646813 is a wasteful number, since it uses less digits than its factorization.

20646813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 625675.

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 20646813 is about 4543.8764287775. The cubic root of 20646813 is about 274.3369724160.

The spelling of 20646813 in words is "twenty million, six hundred forty-six thousand, eight hundred thirteen".