20421829864 has 8 divisors (see below), whose sum is σ = 38290931010. Its totient is φ = 10210914928.

The previous prime is 20421829847. The next prime is 20421829943. The reversal of 20421829864 is 46892812402.

It can be written as a sum of positive squares in only one way, i.e., 19974168900 + 447660964 = 141330^2 + 21158^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×20421829864² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1276364359 + ... + 1276364374.

Almost surely, 2^20421829864 is an apocalyptic number.

It is an amenable number.

20421829864 is a deficient number, since it is larger than the sum of its proper divisors (17869101146).

20421829864 is a wasteful number, since it uses less digits than its factorization.

20421829864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2552728739 (or 2552728735 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 46.

The spelling of 20421829864 in words is "twenty billion, four hundred twenty-one million, eight hundred twenty-nine thousand, eight hundred sixty-four".