1930639681 has 2 divisors, whose sum is σ = 1930639682. Its totient is φ = 1930639680.

The previous prime is 1930639657. The next prime is 1930639699. The reversal of 1930639681 is 1869360391.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1897473600 + 33166081 = 43560^2 + 5759^2 .

It is a cyclic number.

It is not a de Polignac number, because 1930639681 - 2⁷ = 1930639553 is a prime.

It is a super-2 number, since 2×1930639681² = 7454739155703563522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1930619681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 965319840 + 965319841.

It is an arithmetic number, because the mean of its divisors is an integer number (965319841).

Almost surely, 2^1930639681 is an apocalyptic number.

It is an amenable number.

1930639681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1930639681 is an equidigital number, since it uses as much as digits as its factorization.

1930639681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 209952, while the sum is 46.

The square root of 1930639681 is about 43939.0450624499. The cubic root of 1930639681 is about 1245.1846053468.

The spelling of 1930639681 in words is "one billion, nine hundred thirty million, six hundred thirty-nine thousand, six hundred eighty-one".