90921777720 has 256 divisors, whose sum is σ = 283855104000. Its totient is φ = 23283326976.

The previous prime is 90921777719. The next prime is 90921777803. The reversal of 90921777720 is 2777712909.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 126455521 + ... + 126456239.

It is an arithmetic number, because the mean of its divisors is an integer number (1108809000).

Almost surely, 2^90921777720 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 90921777720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141927552000).

90921777720 is an abundant number, since it is smaller than the sum of its proper divisors (192933326280).

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

90921777720 is a wasteful number, since it uses less digits than its factorization.

90921777720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1182 (or 1178 counting only the distinct ones).

The product of its (nonzero) digits is 777924, while the sum is 51.

The spelling of 90921777720 in words is "ninety billion, nine hundred twenty-one million, seven hundred seventy-seven thousand, seven hundred twenty".