91991740 has 12 divisors (see below), whose sum is σ = 193182696. Its totient is φ = 36796688.

The previous prime is 91991719. The next prime is 91991761. The reversal of 91991740 is 4719919.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (91991719) and next prime (91991761).

It is a junction number, because it is equal to n+sod(n) for n = 91991693 and 91991702.

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, 2299774 + ... + 2299813.

It is an arithmetic number, because the mean of its divisors is an integer number (16098558).

Almost surely, 2^91991740 is an apocalyptic number.

It is an amenable number.

91991740 is an abundant number, since it is smaller than the sum of its proper divisors (101190956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91991740 is a wasteful number, since it uses less digits than its factorization.

91991740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4599596 (or 4599594 counting only the distinct ones).

The product of its (nonzero) digits is 20412, while the sum is 40.

The square root of 91991740 is about 9591.2324546953. The cubic root of 91991740 is about 451.4222327835.

The spelling of 91991740 in words is "ninety-one million, nine hundred ninety-one thousand, seven hundred forty".