90807421 has 4 divisors (see below), whose sum is σ = 96149052. Its totient is φ = 85465792.

The previous prime is 90807397. The next prime is 90807433. The reversal of 90807421 is 12470809.

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 72914521 + 17892900 = 8539^2 + 4230^2 .

It is a cyclic number.

It is not a de Polignac number, because 90807421 - 2⁷ = 90807293 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90807121) 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, 2670790 + ... + 2670823.

It is an arithmetic number, because the mean of its divisors is an integer number (24037263).

Almost surely, 2^90807421 is an apocalyptic number.

It is an amenable number.

90807421 is a deficient number, since it is larger than the sum of its proper divisors (5341631).

90807421 is a wasteful number, since it uses less digits than its factorization.

90807421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5341630.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 90807421 is about 9529.2927859312. The cubic root of 90807421 is about 449.4766277422.

The spelling of 90807421 in words is "ninety million, eight hundred seven thousand, four hundred twenty-one".