1938890681 has 16 divisors (see below), whose sum is σ = 2526701184. Its totient is φ = 1443826944.

The previous prime is 1938890677. The next prime is 1938890693. The reversal of 1938890681 is 1860988391.

It is not a de Polignac number, because 1938890681 - 2² = 1938890677 is a prime.

It is a super-2 number, since 2×1938890681² = 7518594145737287522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1938890621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 625115 + ... + 628208.

It is an arithmetic number, because the mean of its divisors is an integer number (157918824).

Almost surely, 2^1938890681 is an apocalyptic number.

It is an amenable number.

1938890681 is a deficient number, since it is larger than the sum of its proper divisors (587810503).

1938890681 is a wasteful number, since it uses less digits than its factorization.

1938890681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1253360.

The product of its (nonzero) digits is 746496, while the sum is 53.

The square root of 1938890681 is about 44032.8363951268. The cubic root of 1938890681 is about 1246.9559382480.

The spelling of 1938890681 in words is "one billion, nine hundred thirty-eight million, eight hundred ninety thousand, six hundred eighty-one".