90135821 has 4 divisors (see below), whose sum is σ = 90154944. Its totient is φ = 90116700.

The previous prime is 90135809. The next prime is 90135833. The reversal of 90135821 is 12853109.

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 an interprime number because it is at equal distance from previous prime (90135809) and next prime (90135833).

It is a cyclic number.

It is not a de Polignac number, because 90135821 - 2¹⁰ = 90134797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90135841) 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, 3086 + ... + 13776.

It is an arithmetic number, because the mean of its divisors is an integer number (22538736).

Almost surely, 2^90135821 is an apocalyptic number.

It is an amenable number.

90135821 is a deficient number, since it is larger than the sum of its proper divisors (19123).

90135821 is a wasteful number, since it uses less digits than its factorization.

90135821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19122.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 90135821 is about 9493.9886770524. The cubic root of 90135821 is about 448.3657942651.

The spelling of 90135821 in words is "ninety million, one hundred thirty-five thousand, eight hundred twenty-one".