20570621 has 4 divisors (see below), whose sum is σ = 20580000. Its totient is φ = 20561244.

The previous prime is 20570609. The next prime is 20570647. The reversal of 20570621 is 12607502.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20570621 - 2²² = 16376317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20570681) 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, 560 + ... + 6438.

It is an arithmetic number, because the mean of its divisors is an integer number (5145000).

Almost surely, 2^20570621 is an apocalyptic number.

It is an amenable number.

20570621 is a deficient number, since it is larger than the sum of its proper divisors (9379).

20570621 is an equidigital number, since it uses as much as digits as its factorization.

20570621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9378.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 20570621 is about 4535.4846488551. The cubic root of 20570621 is about 273.9990986881. Note that the first 3 decimals are identical.

The spelling of 20570621 in words is "twenty million, five hundred seventy thousand, six hundred twenty-one".