20620993 has 4 divisors (see below), whose sum is σ = 20744640. Its totient is φ = 20497348.

The previous prime is 20620987. The next prime is 20620997. The reversal of 20620993 is 39902602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20620993 - 2⁵ = 20620961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20620997) 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, 61573 + ... + 61906.

It is an arithmetic number, because the mean of its divisors is an integer number (5186160).

Almost surely, 2^20620993 is an apocalyptic number.

It is an amenable number.

20620993 is a deficient number, since it is larger than the sum of its proper divisors (123647).

20620993 is a wasteful number, since it uses less digits than its factorization.

20620993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123646.

The product of its (nonzero) digits is 5832, while the sum is 31.

The square root of 20620993 is about 4541.0343535366. The cubic root of 20620993 is about 274.2225667786. Note that the first 3 decimals are identical.

The spelling of 20620993 in words is "twenty million, six hundred twenty thousand, nine hundred ninety-three".