20621723 has 4 divisors (see below), whose sum is σ = 20633760. Its totient is φ = 20609688.

The previous prime is 20621693. The next prime is 20621759. The reversal of 20621723 is 32712602.

It is a semiprime because it is the product of two primes, 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 20621723 - 2¹² = 20617627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20671723) 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, 2915 + ... + 7052.

It is an arithmetic number, because the mean of its divisors is an integer number (5158440).

Almost surely, 2^20621723 is an apocalyptic number.

20621723 is a deficient number, since it is larger than the sum of its proper divisors (12037).

20621723 is an equidigital number, since it uses as much as digits as its factorization.

20621723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12036.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 20621723 is about 4541.1147309884. The cubic root of 20621723 is about 274.2258026414.

The spelling of 20621723 in words is "twenty million, six hundred twenty-one thousand, seven hundred twenty-three".