90646781 has 4 divisors (see below), whose sum is σ = 93096732. Its totient is φ = 88196832.

The previous prime is 90646769. The next prime is 90646789. The reversal of 90646781 is 18764609.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 82973881 + 7672900 = 9109^2 + 2770^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90646781 is a prime.

It is a super-2 number, since 2×90646781² = 16433677811323922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90646789) 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, 1224920 + ... + 1224993.

It is an arithmetic number, because the mean of its divisors is an integer number (23274183).

Almost surely, 2^90646781 is an apocalyptic number.

It is an amenable number.

90646781 is a deficient number, since it is larger than the sum of its proper divisors (2449951).

90646781 is a wasteful number, since it uses less digits than its factorization.

90646781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2449950.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 90646781 is about 9520.8603077663. The cubic root of 90646781 is about 449.2114271551.

The spelling of 90646781 in words is "ninety million, six hundred forty-six thousand, seven hundred eighty-one".