91150251921 has 27 divisors (see below), whose sum is σ = 132712463793. Its totient is φ = 60285588480.

The previous prime is 91150251919. The next prime is 91150251931. The reversal of 91150251921 is 12915205119.

The square root of 91150251921 is 301911.

It is a perfect power (a square), and thus also a powerful number.

91150251921 is a `hidden beast` number, since 9 + 11 + 502 + 51 + 92 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 5790449025 + 85359802896 = 76095^2 + 292164^2 .

It is not a de Polignac number, because 91150251921 - 2¹ = 91150251919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (91150251931) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 142199761 + ... + 142200401.

Almost surely, 2^91150251921 is an apocalyptic number.

91150251921 is the 301911-st square number.

91150251921 is the 150956-th centered octagonal number.

It is an amenable number.

91150251921 is a deficient number, since it is larger than the sum of its proper divisors (41562211872).

91150251921 is an frugal number, since it uses more digits than its factorization.

91150251921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1602 (or 801 counting only the distinct ones).

The product of its (nonzero) digits is 8100, while the sum is 36.

Multiplying 91150251921 by its sum of digits (36), we get a square (3281409069156 = 1811466²).

Multiplying 91150251921 by its product of nonzero digits (8100), we get a square (738317040560100 = 27171990²).

The spelling of 91150251921 in words is "ninety-one billion, one hundred fifty million, two hundred fifty-one thousand, nine hundred twenty-one".