401904013681 has 9 divisors (see below), whose sum is σ = 407690019723. Its totient is φ = 396199016640.

The previous prime is 401904013663. The next prime is 401904013699. The reversal of 401904013681 is 186310409104.

The square root of 401904013681 is 633959.

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

It is an interprime number because it is at equal distance from previous prime (401904013663) and next prime (401904013699).

It can be written as a sum of positive squares in only one way, i.e., 15069772081 + 386834241600 = 122759^2 + 621960^2 .

It is not a de Polignac number, because 401904013681 - 2¹⁵ = 401903980913 is a prime.

It is a super-2 number, since 2×401904013681² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 401904013681.

It is not an unprimeable number, because it can be changed into a prime (401904013661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 45006625 + ... + 45015553.

Almost surely, 2^401904013681 is an apocalyptic number.

401904013681 is the 633959-th square number.

401904013681 is the 316980-th centered octagonal number.

It is an amenable number.

401904013681 is a deficient number, since it is larger than the sum of its proper divisors (5786006042).

401904013681 is an frugal number, since it uses more digits than its factorization.

401904013681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18000 (or 9000 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 37.

The spelling of 401904013681 in words is "four hundred one billion, nine hundred four million, thirteen thousand, six hundred eighty-one".