90778640 has 40 divisors (see below), whose sum is σ = 223479000. Its totient is φ = 34174976.

The previous prime is 90778621. The next prime is 90778651. The reversal of 90778640 is 4687709.

It can be written as a sum of positive squares in 4 ways, for example, as 23931664 + 66846976 = 4892^2 + 8176^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×90778640² = 16481522960499200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32015 + ... + 34734.

It is an arithmetic number, because the mean of its divisors is an integer number (5586975).

Almost surely, 2^90778640 is an apocalyptic number.

It is an amenable number.

90778640 is an abundant number, since it is smaller than the sum of its proper divisors (132700360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

90778640 is a wasteful number, since it uses less digits than its factorization.

90778640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66779 (or 66773 counting only the distinct ones).

The product of its (nonzero) digits is 84672, while the sum is 41.

The square root of 90778640 is about 9527.7825332026. The cubic root of 90778640 is about 449.4291361986.

The spelling of 90778640 in words is "ninety million, seven hundred seventy-eight thousand, six hundred forty".