90784781 has 4 divisors (see below), whose sum is σ = 90812352. Its totient is φ = 90757212.

The previous prime is 90784753. The next prime is 90784801. The reversal of 90784781 is 18748709.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18748709 = 7 ⋅2678387.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-90784781 is a prime.

It is a super-2 number, since 2×90784781² = 16483752922435922, 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 (90784721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8051 + ... + 15696.

It is an arithmetic number, because the mean of its divisors is an integer number (22703088).

Almost surely, 2^90784781 is an apocalyptic number.

It is an amenable number.

90784781 is a deficient number, since it is larger than the sum of its proper divisors (27571).

90784781 is a wasteful number, since it uses less digits than its factorization.

90784781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27570.

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 90784781 is about 9528.1047958133. The cubic root of 90784781 is about 449.4392703083.

The spelling of 90784781 in words is "ninety million, seven hundred eighty-four thousand, seven hundred eighty-one".