68891987 has 2 divisors, whose sum is σ = 68891988. Its totient is φ = 68891986.

The previous prime is 68891971. The next prime is 68892037. The reversal of 68891987 is 78919886.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 68891987 - 2⁴ = 68891971 is a prime.

It is a super-2 number, since 2×68891987² = 9492211745616338, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (68891287) by changing a digit.

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 as a sum of consecutive naturals, namely, 34445993 + 34445994.

It is an arithmetic number, because the mean of its divisors is an integer number (34445994).

Almost surely, 2^68891987 is an apocalyptic number.

68891987 is a deficient number, since it is larger than the sum of its proper divisors (1).

68891987 is an equidigital number, since it uses as much as digits as its factorization.

68891987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1741824, while the sum is 56.

The square root of 68891987 is about 8300.1196979321. The cubic root of 68891987 is about 409.9424606939.

The spelling of 68891987 in words is "sixty-eight million, eight hundred ninety-one thousand, nine hundred eighty-seven".