398877632981 has 4 divisors (see below), whose sum is σ = 399593751372. Its totient is φ = 398161514592.

The previous prime is 398877632977. The next prime is 398877632999. The reversal of 398877632981 is 189236778893.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 211554002500 + 187323630481 = 459950^2 + 432809^2 .

It is a cyclic number.

It is not a de Polignac number, because 398877632981 - 2² = 398877632977 is a prime.

It is a super-2 number, since 2×398877632981² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398877632911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 358058360 + ... + 358059473.

It is an arithmetic number, because the mean of its divisors is an integer number (99898437843).

Almost surely, 2^398877632981 is an apocalyptic number.

It is an amenable number.

398877632981 is a deficient number, since it is larger than the sum of its proper divisors (716118391).

398877632981 is an equidigital number, since it uses as much as digits as its factorization.

398877632981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 716118390.

The product of its digits is 219469824, while the sum is 71.

The spelling of 398877632981 in words is "three hundred ninety-eight billion, eight hundred seventy-seven million, six hundred thirty-two thousand, nine hundred eighty-one".