91661428 has 12 divisors (see below), whose sum is σ = 162605380. Its totient is φ = 45202752.

The previous prime is 91661413. The next prime is 91661441. The reversal of 91661428 is 82416619.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 69022864 + 22638564 = 8308^2 + 4758^2 .

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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, 156663 + ... + 157246.

Almost surely, 2^91661428 is an apocalyptic number.

It is an amenable number.

91661428 is a deficient number, since it is larger than the sum of its proper divisors (70943952).

91661428 is a wasteful number, since it uses less digits than its factorization.

91661428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 313986 (or 313984 counting only the distinct ones).

The product of its digits is 20736, while the sum is 37.

The square root of 91661428 is about 9573.9974932105. The cubic root of 91661428 is about 450.8812820202.

The spelling of 91661428 in words is "ninety-one million, six hundred sixty-one thousand, four hundred twenty-eight".