91618666 has 4 divisors (see below), whose sum is σ = 137428002. Its totient is φ = 45809332.

The previous prime is 91618633. The next prime is 91618687. The reversal of 91618666 is 66681619.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66681619 = 83 ⋅803393.

It can be written as a sum of positive squares in only one way, i.e., 78694641 + 12924025 = 8871^2 + 3595^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22904665 + ... + 22904668.

Almost surely, 2^91618666 is an apocalyptic number.

91618666 is a deficient number, since it is larger than the sum of its proper divisors (45809336).

91618666 is a wasteful number, since it uses less digits than its factorization.

91618666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45809335.

The product of its digits is 93312, while the sum is 43.

The square root of 91618666 is about 9571.7639962548. The cubic root of 91618666 is about 450.8111558873.

The spelling of 91618666 in words is "ninety-one million, six hundred eighteen thousand, six hundred sixty-six".