1938778531 has 16 divisors (see below), whose sum is σ = 2023639200. Its totient is φ = 1856245248.

The previous prime is 1938778511. The next prime is 1938778553. The reversal of 1938778531 is 1358778391.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1938778531 is a prime.

It is a super-2 number, since 2×1938778531² = 7517724384533035922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1938778511) 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, 384555 + ... + 389563.

It is an arithmetic number, because the mean of its divisors is an integer number (126477450).

Almost surely, 2^1938778531 is an apocalyptic number.

1938778531 is a deficient number, since it is larger than the sum of its proper divisors (84860669).

1938778531 is a wasteful number, since it uses less digits than its factorization.

1938778531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5238.

The product of its digits is 1270080, while the sum is 52.

The square root of 1938778531 is about 44031.5628952687. The cubic root of 1938778531 is about 1246.9318954957.

The spelling of 1938778531 in words is "one billion, nine hundred thirty-eight million, seven hundred seventy-eight thousand, five hundred thirty-one".