20640426 has 32 divisors (see below), whose sum is σ = 42985728. Its totient is φ = 6601920.

The previous prime is 20640401. The next prime is 20640437. The reversal of 20640426 is 62404602.

It is a super-2 number, since 2×20640426² = 852054370922952, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20640396 and 20640405.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14256 + ... + 15636.

It is an arithmetic number, because the mean of its divisors is an integer number (1343304).

Almost surely, 2^20640426 is an apocalyptic number.

20640426 is an abundant number, since it is smaller than the sum of its proper divisors (22345302).

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

20640426 is a wasteful number, since it uses less digits than its factorization.

20640426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486.

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 20640426 is about 4543.1735604091. The cubic root of 20640426 is about 274.3086811901.

The spelling of 20640426 in words is "twenty million, six hundred forty thousand, four hundred twenty-six".