91905372261 has 6 divisors (see below), whose sum is σ = 132752204390. Its totient is φ = 61270248168.

The previous prime is 91905372253. The next prime is 91905372263. The reversal of 91905372261 is 16227350919.

It is a happy number.

91905372261 is a `hidden beast` number, since 9 + 1 + 90 + 537 + 2 + 26 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 68903100036 + 23002272225 = 262494^2 + 151665^2 .

It is not a de Polignac number, because 91905372261 - 2³ = 91905372253 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91905372263) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5105854006 + ... + 5105854023.

Almost surely, 2^91905372261 is an apocalyptic number.

It is an amenable number.

91905372261 is a deficient number, since it is larger than the sum of its proper divisors (40846832129).

91905372261 is a wasteful number, since it uses less digits than its factorization.

91905372261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10211708035 (or 10211708032 counting only the distinct ones).

The product of its (nonzero) digits is 204120, while the sum is 45.

It can be divided in two parts, 91905 and 372261, that added together give a triangular number (464166 = T₉₆₃).

The spelling of 91905372261 in words is "ninety-one billion, nine hundred five million, three hundred seventy-two thousand, two hundred sixty-one".