90721221 has 8 divisors (see below), whose sum is σ = 124863744. Its totient is φ = 58529760.

The previous prime is 90721217. The next prime is 90721229. The reversal of 90721221 is 12212709.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 90721221 - 2² = 90721217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 90721191 and 90721200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90721229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 487656 + ... + 487841.

It is an arithmetic number, because the mean of its divisors is an integer number (15607968).

Almost surely, 2^90721221 is an apocalyptic number.

It is an amenable number.

90721221 is a deficient number, since it is larger than the sum of its proper divisors (34142523).

90721221 is a wasteful number, since it uses less digits than its factorization.

90721221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 975531.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 90721221 is about 9524.7688160921. The cubic root of 90721221 is about 449.3343590779.

The spelling of 90721221 in words is "ninety million, seven hundred twenty-one thousand, two hundred twenty-one".