20721426 has 16 divisors (see below), whose sum is σ = 45210528. Its totient is φ = 6279200.

The previous prime is 20721401. The next prime is 20721433. The reversal of 20721426 is 62412702.

It is a junction number, because it is equal to n+sod(n) for n = 20721396 and 20721405.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 156915 + ... + 157046.

It is an arithmetic number, because the mean of its divisors is an integer number (2825658).

Almost surely, 2^20721426 is an apocalyptic number.

20721426 is an abundant number, since it is smaller than the sum of its proper divisors (24489102).

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

20721426 is a wasteful number, since it uses less digits than its factorization.

20721426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313977.

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 20721426 is about 4552.0793051088. The cubic root of 20721426 is about 274.6670394498.

The spelling of 20721426 in words is "twenty million, seven hundred twenty-one thousand, four hundred twenty-six".