90129840 has 80 divisors (see below), whose sum is σ = 280601088. Its totient is φ = 23931648.

The previous prime is 90129799. The next prime is 90129859. The reversal of 90129840 is 4892109.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 67257 + ... + 68583.

Almost surely, 2^90129840 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 90129840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140300544).

90129840 is an abundant number, since it is smaller than the sum of its proper divisors (190471248).

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

90129840 is a wasteful number, since it uses less digits than its factorization.

90129840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1626 (or 1620 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 90129840 is about 9493.6736830376. The cubic root of 90129840 is about 448.3558768793.

The spelling of 90129840 in words is "ninety million, one hundred twenty-nine thousand, eight hundred forty".