90432936721 has 4 divisors (see below), whose sum is σ = 95752521252. Its totient is φ = 85113352192.

The previous prime is 90432936677. The next prime is 90432936733. The reversal of 90432936721 is 12763923409.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12763923409 = 2309 ⋅5527901.

It can be written as a sum of positive squares in 2 ways, for example, as 31235613696 + 59197323025 = 176736^2 + 243305^2 .

It is a de Polignac number, because none of the positive numbers 2^k-90432936721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90432936421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2659792240 + ... + 2659792273.

It is an arithmetic number, because the mean of its divisors is an integer number (23938130313).

Almost surely, 2^90432936721 is an apocalyptic number.

It is an amenable number.

90432936721 is a deficient number, since it is larger than the sum of its proper divisors (5319584531).

90432936721 is a wasteful number, since it uses less digits than its factorization.

90432936721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5319584530.

The product of its (nonzero) digits is 489888, while the sum is 46.

The spelling of 90432936721 in words is "ninety billion, four hundred thirty-two million, nine hundred thirty-six thousand, seven hundred twenty-one".