20401551556 has 27 divisors (see below), whose sum is σ = 37935443847. Its totient is φ = 9598444800.

The previous prime is 20401551529. The next prime is 20401551571. The reversal of 20401551556 is 65515510402.

The square root of 20401551556 is 142834.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 1242562500 + 19158989056 = 35250^2 + 138416^2 .

It is a super-2 number, since 2×20401551556² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 4854256 + ... + 4858456.

Almost surely, 2^20401551556 is an apocalyptic number.

20401551556 is the 142834-th square number.

It is an amenable number.

20401551556 is a deficient number, since it is larger than the sum of its proper divisors (17533892291).

20401551556 is an frugal number, since it uses more digits than its factorization.

20401551556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8440 (or 4220 counting only the distinct ones).

The product of its (nonzero) digits is 30000, while the sum is 34.

The spelling of 20401551556 in words is "twenty billion, four hundred one million, five hundred fifty-one thousand, five hundred fifty-six".