91821209504 has 12 divisors (see below), whose sum is σ = 180773006274. Its totient is φ = 45910604736.

The previous prime is 91821209497. The next prime is 91821209521. The reversal of 91821209504 is 40590212819.

It can be written as a sum of positive squares in only one way, i.e., 52358592400 + 39462617104 = 228820^2 + 198652^2 .

It is a super-2 number, since 2×91821209504² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1434706367 + ... + 1434706430.

Almost surely, 2^91821209504 is an apocalyptic number.

It is an amenable number.

91821209504 is a deficient number, since it is larger than the sum of its proper divisors (88951796770).

91821209504 is a wasteful number, since it uses less digits than its factorization.

91821209504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2869412807 (or 2869412799 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 41.

The spelling of 91821209504 in words is "ninety-one billion, eight hundred twenty-one million, two hundred nine thousand, five hundred four".