20721726 has 24 divisors (see below), whose sum is σ = 44984160. Its totient is φ = 6893856.

The previous prime is 20721721. The next prime is 20721737. The reversal of 20721726 is 62712702.

It is a self number, because there is not a number n which added to its sum of digits gives 20721726.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20721721) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13851 + ... + 15273.

It is an arithmetic number, because the mean of its divisors is an integer number (1874340).

Almost surely, 2^20721726 is an apocalyptic number.

20721726 is an abundant number, since it is smaller than the sum of its proper divisors (24262434).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20721726 is a wasteful number, since it uses less digits than its factorization.

20721726 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2240 (or 2237 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 27.

The square root of 20721726 is about 4552.1122569638. The cubic root of 20721726 is about 274.6683649653.

The spelling of 20721726 in words is "twenty million, seven hundred twenty-one thousand, seven hundred twenty-six".