89428721 has 8 divisors (see below), whose sum is σ = 97954920. Its totient is φ = 81265408.

The previous prime is 89428699. The next prime is 89428739. The reversal of 89428721 is 12782498.

It can be written as a sum of positive squares in 4 ways, for example, as 12673600 + 76755121 = 3560^2 + 8761^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-89428721 is a prime.

It is a super-2 number, since 2×89428721² = 15994992279391682, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (89428751) 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, 90206 + ... + 91191.

It is an arithmetic number, because the mean of its divisors is an integer number (12244365).

Almost surely, 2^89428721 is an apocalyptic number.

It is an amenable number.

89428721 is a deficient number, since it is larger than the sum of its proper divisors (8526199).

89428721 is a wasteful number, since it uses less digits than its factorization.

89428721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 181443.

The product of its digits is 64512, while the sum is 41.

The square root of 89428721 is about 9456.6760016403. The cubic root of 89428721 is about 447.1902641161.

The spelling of 89428721 in words is "eighty-nine million, four hundred twenty-eight thousand, seven hundred twenty-one".