1686990281 has 2 divisors, whose sum is σ = 1686990282. Its totient is φ = 1686990280.

The previous prime is 1686990251. The next prime is 1686990289. The reversal of 1686990281 is 1820996861.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1684692025 + 2298256 = 41045^2 + 1516^2 .

It is a cyclic number.

It is not a de Polignac number, because 1686990281 - 2²² = 1682795977 is a prime.

It is a super-2 number, since 2×1686990281² = 5691872416376917922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1686990289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 843495140 + 843495141.

It is an arithmetic number, because the mean of its divisors is an integer number (843495141).

Almost surely, 2^1686990281 is an apocalyptic number.

It is an amenable number.

1686990281 is a deficient number, since it is larger than the sum of its proper divisors (1).

1686990281 is an equidigital number, since it uses as much as digits as its factorization.

1686990281 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 373248, while the sum is 50.

The square root of 1686990281 is about 41072.9872422253. The cubic root of 1686990281 is about 1190.4309060194.

The spelling of 1686990281 in words is "one billion, six hundred eighty-six million, nine hundred ninety thousand, two hundred eighty-one".