90978689 has 2 divisors, whose sum is σ = 90978690. Its totient is φ = 90978688.

The previous prime is 90978677. The next prime is 90978733. The reversal of 90978689 is 98687909.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52128400 + 38850289 = 7220^2 + 6233^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90978689 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (90978089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45489344 + 45489345.

It is an arithmetic number, because the mean of its divisors is an integer number (45489345).

Almost surely, 2^90978689 is an apocalyptic number.

It is an amenable number.

90978689 is a deficient number, since it is larger than the sum of its proper divisors (1).

90978689 is an equidigital number, since it uses as much as digits as its factorization.

90978689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1959552, while the sum is 56.

The square root of 90978689 is about 9538.2749488574. The cubic root of 90978689 is about 449.7590298338.

The spelling of 90978689 in words is "ninety million, nine hundred seventy-eight thousand, six hundred eighty-nine".