68981690 has 16 divisors (see below), whose sum is σ = 127523592. Its totient is φ = 26846784.

The previous prime is 68981681. The next prime is 68981707. The reversal of 68981690 is 9618986.

It can be written as a sum of positive squares in 4 ways, for example, as 68343289 + 638401 = 8267^2 + 799^2 .

It is a super-2 number, since 2×68981690² = 9516947110512200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 92849 + ... + 93588.

Almost surely, 2^68981690 is an apocalyptic number.

68981690 is a deficient number, since it is larger than the sum of its proper divisors (58541902).

68981690 is a wasteful number, since it uses less digits than its factorization.

68981690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186481.

The product of its (nonzero) digits is 186624, while the sum is 47.

The square root of 68981690 is about 8305.5216573073. The cubic root of 68981690 is about 410.1203097258.

The spelling of 68981690 in words is "sixty-eight million, nine hundred eighty-one thousand, six hundred ninety".