90397821 has 4 divisors (see below), whose sum is σ = 120530432. Its totient is φ = 60265212.

The previous prime is 90397819. The next prime is 90397837. The reversal of 90397821 is 12879309.

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.

It is not a de Polignac number, because 90397821 - 2¹ = 90397819 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 90397821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90397861) 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, 15066301 + ... + 15066306.

It is an arithmetic number, because the mean of its divisors is an integer number (30132608).

Almost surely, 2^90397821 is an apocalyptic number.

It is an amenable number.

90397821 is a deficient number, since it is larger than the sum of its proper divisors (30132611).

90397821 is a wasteful number, since it uses less digits than its factorization.

90397821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30132610.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 90397821 is about 9507.7768694895. The cubic root of 90397821 is about 448.7997993063.

The spelling of 90397821 in words is "ninety million, three hundred ninety-seven thousand, eight hundred twenty-one".