20258721 has 32 divisors (see below), whose sum is σ = 35239680. Its totient is φ = 11259648.

The previous prime is 20258663. The next prime is 20258737. The reversal of 20258721 is 12785202.

It is not a de Polignac number, because 20258721 - 2⁶ = 20258657 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (20258621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5545 + ... + 8441.

It is an arithmetic number, because the mean of its divisors is an integer number (1101240).

Almost surely, 2^20258721 is an apocalyptic number.

20258721 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20258721 is a deficient number, since it is larger than the sum of its proper divisors (14980959).

20258721 is a wasteful number, since it uses less digits than its factorization.

20258721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2950 (or 2944 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 20258721 is about 4500.9688956935. The cubic root of 20258721 is about 272.6072119725.

The spelling of 20258721 in words is "twenty million, two hundred fifty-eight thousand, seven hundred twenty-one".