90016921 has 4 divisors (see below), whose sum is σ = 95312052. Its totient is φ = 84721792.

The previous prime is 90016919. The next prime is 90016951. The reversal of 90016921 is 12961009.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12961009 = 131 ⋅98939.

It can be written as a sum of positive squares in 2 ways, for example, as 28472896 + 61544025 = 5336^2 + 7845^2 .

It is a cyclic number.

It is not a de Polignac number, because 90016921 - 2¹ = 90016919 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 90016921.

It is not an unprimeable number, because it can be changed into a prime (90016951) 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, 2647540 + ... + 2647573.

It is an arithmetic number, because the mean of its divisors is an integer number (23828013).

Almost surely, 2^90016921 is an apocalyptic number.

It is an amenable number.

90016921 is a deficient number, since it is larger than the sum of its proper divisors (5295131).

90016921 is a wasteful number, since it uses less digits than its factorization.

90016921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5295130.

The product of its (nonzero) digits is 972, while the sum is 28.

The square root of 90016921 is about 9487.7247535961. The cubic root of 90016921 is about 448.1685580253.

The spelling of 90016921 in words is "ninety million, sixteen thousand, nine hundred twenty-one".