90078840657 has 24 divisors (see below), whose sum is σ = 143909746344. Its totient is φ = 53934937344.

The previous prime is 90078840641. The next prime is 90078840721. The reversal of 90078840657 is 75604887009.

It can be written as a sum of positive squares in 4 ways, for example, as 2746179216 + 87332661441 = 52404^2 + 295521^2 .

It is not a de Polignac number, because 90078840657 - 2⁴ = 90078840641 is a prime.

It is a super-3 number, since 3×90078840657³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (90078840557) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10399788 + ... + 10408445.

It is an arithmetic number, because the mean of its divisors is an integer number (5996239431).

Almost surely, 2^90078840657 is an apocalyptic number.

It is an amenable number.

90078840657 is a deficient number, since it is larger than the sum of its proper divisors (53830905687).

90078840657 is a wasteful number, since it uses less digits than its factorization.

90078840657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20808289 (or 20808286 counting only the distinct ones).

The product of its (nonzero) digits is 3386880, while the sum is 54.

The spelling of 90078840657 in words is "ninety billion, seventy-eight million, eight hundred forty thousand, six hundred fifty-seven".