1931681 has 2 divisors, whose sum is σ = 1931682. Its totient is φ = 1931680.

The previous prime is 1931669. The next prime is 1931717. The reversal of 1931681 is 1861391.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1918225 + 13456 = 1385^2 + 116^2 .

It is a cyclic number.

It is not a de Polignac number, because 1931681 - 2¹⁸ = 1669537 is a prime.

It is a super-2 number, since 2×1931681² = 7462782971522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1931651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 965840 + 965841.

It is an arithmetic number, because the mean of its divisors is an integer number (965841).

2^1931681 is an apocalyptic number.

It is an amenable number.

1931681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1931681 is an equidigital number, since it uses as much as digits as its factorization.

1931681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 29.

The square root of 1931681 is about 1389.8492724033. The cubic root of 1931681 is about 124.5408434673.

The spelling of 1931681 in words is "one million, nine hundred thirty-one thousand, six hundred eighty-one".