90721019 has 4 divisors (see below), whose sum is σ = 93849360. Its totient is φ = 87592680.

The previous prime is 90720997. The next prime is 90721021. The reversal of 90721019 is 91012709.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 90721019 - 2¹⁶ = 90655483 is a prime.

It is a super-2 number, since 2×90721019² = 16460606576796722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 3128311 = 90721019 / (9 + 0 + 7 + 2 + 1 + 0 + 1 + 9).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 90720982 and 90721000.

It is not an unprimeable number, because it can be changed into a prime (90721049) 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, 1564127 + ... + 1564184.

It is an arithmetic number, because the mean of its divisors is an integer number (23462340).

Almost surely, 2^90721019 is an apocalyptic number.

90721019 is a deficient number, since it is larger than the sum of its proper divisors (3128341).

90721019 is a wasteful number, since it uses less digits than its factorization.

90721019 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3128340.

The product of its (nonzero) digits is 1134, while the sum is 29.

The square root of 90721019 is about 9524.7582121543. The cubic root of 90721019 is about 449.3340255815.

The spelling of 90721019 in words is "ninety million, seven hundred twenty-one thousand, nineteen".