90420915640 has 256 divisors, whose sum is σ = 238225536000. Its totient is φ = 30541639680.

The previous prime is 90420915631. The next prime is 90420915653. The reversal of 90420915640 is 4651902409.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 90420915593 and 90420915602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 139753797 + ... + 139754443.

It is an arithmetic number, because the mean of its divisors is an integer number (930568500).

Almost surely, 2^90420915640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 90420915640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119112768000).

90420915640 is an abundant number, since it is smaller than the sum of its proper divisors (147804620360).

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

90420915640 is a wasteful number, since it uses less digits than its factorization.

90420915640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 990 (or 986 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 40.

The spelling of 90420915640 in words is "ninety billion, four hundred twenty million, nine hundred fifteen thousand, six hundred forty".