38891389681 has 9 divisors (see below), whose sum is σ = 39127288473. Its totient is φ = 38656908180.

The previous prime is 38891389661. The next prime is 38891389727. The reversal of 38891389681 is 18698319883.

The square root of 38891389681 is 197209.

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

It is not a de Polignac number, because 38891389681 - 2²¹ = 38889292529 is a prime.

It is a super-2 number, since 2×38891389681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (38891389601) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 39244096 + ... + 39245086.

It is an arithmetic number, because the mean of its divisors is an integer number (4347476497).

Almost surely, 2^38891389681 is an apocalyptic number.

38891389681 is the 197209-th square number.

38891389681 is the 98605-th centered octagonal number.

It is an amenable number.

38891389681 is a deficient number, since it is larger than the sum of its proper divisors (235898792).

38891389681 is an frugal number, since it uses more digits than its factorization.

38891389681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2380 (or 1190 counting only the distinct ones).

The product of its digits is 17915904, while the sum is 64.

Multiplying 38891389681 by its sum of digits (64), we get a square (2489048939584 = 1577672²).

The spelling of 38891389681 in words is "thirty-eight billion, eight hundred ninety-one million, three hundred eighty-nine thousand, six hundred eighty-one".