20732421 has 4 divisors (see below), whose sum is σ = 27643232. Its totient is φ = 13821612.

The previous prime is 20732399. The next prime is 20732441. The reversal of 20732421 is 12423702.

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 not a de Polignac number, because 20732421 - 2⁵ = 20732389 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 (20732441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3455401 + ... + 3455406.

It is an arithmetic number, because the mean of its divisors is an integer number (6910808).

Almost surely, 2^20732421 is an apocalyptic number.

It is an amenable number.

20732421 is a deficient number, since it is larger than the sum of its proper divisors (6910811).

20732421 is an equidigital number, since it uses as much as digits as its factorization.

20732421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6910810.

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 20732421 is about 4553.2868348041. The cubic root of 20732421 is about 274.7156112375.

The spelling of 20732421 in words is "twenty million, seven hundred thirty-two thousand, four hundred twenty-one".