20772421 has 4 divisors (see below), whose sum is σ = 20849344. Its totient is φ = 20695500.

The previous prime is 20772403. The next prime is 20772443. The reversal of 20772421 is 12427702.

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 20772421 - 2⁷ = 20772293 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 (20772481) 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, 38055 + ... + 38596.

It is an arithmetic number, because the mean of its divisors is an integer number (5212336).

Almost surely, 2^20772421 is an apocalyptic number.

It is an amenable number.

20772421 is a deficient number, since it is larger than the sum of its proper divisors (76923).

20772421 is an equidigital number, since it uses as much as digits as its factorization.

20772421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76922.

The product of its (nonzero) digits is 1568, while the sum is 25.

The square root of 20772421 is about 4557.6771496015. The cubic root of 20772421 is about 274.8921714997.

The spelling of 20772421 in words is "twenty million, seven hundred seventy-two thousand, four hundred twenty-one".