90778913 has 4 divisors (see below), whose sum is σ = 90842928. Its totient is φ = 90714900.

The previous prime is 90778873. The next prime is 90778927. The reversal of 90778913 is 31987709.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31987709 = 13 ⋅2460593.

It is a cyclic number.

It is not a de Polignac number, because 90778913 - 2²² = 86584609 is a prime.

It is a super-2 number, since 2×90778913² = 16481622090923138, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90778313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29831 + ... + 32732.

It is an arithmetic number, because the mean of its divisors is an integer number (22710732).

Almost surely, 2^90778913 is an apocalyptic number.

It is an amenable number.

90778913 is a deficient number, since it is larger than the sum of its proper divisors (64015).

90778913 is a wasteful number, since it uses less digits than its factorization.

90778913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64014.

The product of its (nonzero) digits is 95256, while the sum is 44.

The square root of 90778913 is about 9527.7968597153. The cubic root of 90778913 is about 449.4295867232.

The spelling of 90778913 in words is "ninety million, seven hundred seventy-eight thousand, nine hundred thirteen".