20809858402 has 16 divisors (see below), whose sum is σ = 32292732024. Its totient is φ = 10050640000.

The previous prime is 20809858393. The next prime is 20809858417. The reversal of 20809858402 is 20485890802.

It can be written as a sum of positive squares in 4 ways, for example, as 12651975361 + 8157883041 = 112481^2 + 90321^2 .

It is a super-2 number, since 2×20809858402² (a number of 21 digits) contains 22 as substring.

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, 1248049 + ... + 1264612.

Almost surely, 2^20809858402 is an apocalyptic number.

20809858402 is a deficient number, since it is larger than the sum of its proper divisors (11482873622).

20809858402 is a wasteful number, since it uses less digits than its factorization.

20809858402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2512805.

The product of its (nonzero) digits is 368640, while the sum is 46.

The spelling of 20809858402 in words is "twenty billion, eight hundred nine million, eight hundred fifty-eight thousand, four hundred two".