91289906 has 4 divisors (see below), whose sum is σ = 136934862. Its totient is φ = 45644952.

The previous prime is 91289899. The next prime is 91289923. The reversal of 91289906 is 60998219.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 60998219 = 2789 ⋅21871.

It can be written as a sum of positive squares in only one way, i.e., 54626881 + 36663025 = 7391^2 + 6055^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22822475 + ... + 22822478.

Almost surely, 2^91289906 is an apocalyptic number.

91289906 is a deficient number, since it is larger than the sum of its proper divisors (45644956).

91289906 is a wasteful number, since it uses less digits than its factorization.

91289906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45644955.

The product of its (nonzero) digits is 69984, while the sum is 44.

The square root of 91289906 is about 9554.5751344578. The cubic root of 91289906 is about 450.2712866253.

The spelling of 91289906 in words is "ninety-one million, two hundred eighty-nine thousand, nine hundred six".