90219021 has 32 divisors (see below), whose sum is σ = 128099328. Its totient is φ = 56401920.

The previous prime is 90219013. The next prime is 90219047. The reversal of 90219021 is 12091209.

It is not a de Polignac number, because 90219021 - 2³ = 90219013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 90218982 and 90219000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90219001) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 658465 + ... + 658601.

It is an arithmetic number, because the mean of its divisors is an integer number (4003104).

Almost surely, 2^90219021 is an apocalyptic number.

It is an amenable number.

90219021 is a deficient number, since it is larger than the sum of its proper divisors (37880307).

90219021 is a wasteful number, since it uses less digits than its factorization.

90219021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341.

The product of its (nonzero) digits is 324, while the sum is 24.

The square root of 90219021 is about 9498.3693863736. The cubic root of 90219021 is about 448.5037067387.

The spelling of 90219021 in words is "ninety million, two hundred nineteen thousand, twenty-one".