90121618 has 8 divisors (see below), whose sum is σ = 139843980. Its totient is φ = 43506960.

The previous prime is 90121609. The next prime is 90121627. The reversal of 90121618 is 81612109.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (90121609) and next prime (90121627).

It can be written as a sum of positive squares in 2 ways, for example, as 85988529 + 4133089 = 9273^2 + 2033^2 .

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

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 776853 + ... + 776968.

Almost surely, 2^90121618 is an apocalyptic number.

90121618 is a deficient number, since it is larger than the sum of its proper divisors (49722362).

90121618 is a wasteful number, since it uses less digits than its factorization.

90121618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1553852.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 90121618 is about 9493.2406479558. The cubic root of 90121618 is about 448.3422428667.

The spelling of 90121618 in words is "ninety million, one hundred twenty-one thousand, six hundred eighteen".