90747821 has 2 divisors, whose sum is σ = 90747822. Its totient is φ = 90747820.

The previous prime is 90747817. The next prime is 90747851. The reversal of 90747821 is 12874709.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 89775625 + 972196 = 9475^2 + 986^2 .

It is a cyclic number.

It is not a de Polignac number, because 90747821 - 2² = 90747817 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (90747851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45373910 + 45373911.

It is an arithmetic number, because the mean of its divisors is an integer number (45373911).

Almost surely, 2^90747821 is an apocalyptic number.

It is an amenable number.

90747821 is a deficient number, since it is larger than the sum of its proper divisors (1).

90747821 is an equidigital number, since it uses as much as digits as its factorization.

90747821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 90747821 is about 9526.1650731026. The cubic root of 90747821 is about 449.3782706194.

The spelling of 90747821 in words is "ninety million, seven hundred forty-seven thousand, eight hundred twenty-one".