90640391 has 2 divisors, whose sum is σ = 90640392. Its totient is φ = 90640390.

The previous prime is 90640349. The next prime is 90640411. The reversal of 90640391 is 19304609.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 90640391 - 2¹⁴ = 90624007 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90640301) 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 as a sum of consecutive naturals, namely, 45320195 + 45320196.

It is an arithmetic number, because the mean of its divisors is an integer number (45320196).

Almost surely, 2^90640391 is an apocalyptic number.

90640391 is a deficient number, since it is larger than the sum of its proper divisors (1).

90640391 is an equidigital number, since it uses as much as digits as its factorization.

90640391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 32.

The square root of 90640391 is about 9520.5247229341. The cubic root of 90640391 is about 449.2008714265.

The spelling of 90640391 in words is "ninety million, six hundred forty thousand, three hundred ninety-one".