1891336521 has 16 divisors (see below), whose sum is σ = 2565186624. Its totient is φ = 1239344064.

The previous prime is 1891336507. The next prime is 1891336543. The reversal of 1891336521 is 1256331981.

It is a de Polignac number, because none of the positive numbers 2^k-1891336521 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1891336521.

It is not an unprimeable number, because it can be changed into a prime (1891331521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29775 + ... + 68331.

It is an arithmetic number, because the mean of its divisors is an integer number (160324164).

Almost surely, 2^1891336521 is an apocalyptic number.

It is an amenable number.

1891336521 is a deficient number, since it is larger than the sum of its proper divisors (673850103).

1891336521 is a wasteful number, since it uses less digits than its factorization.

1891336521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38840.

The product of its digits is 38880, while the sum is 39.

The square root of 1891336521 is about 43489.4989738902. The cubic root of 1891336521 is about 1236.6769595977.

The spelling of 1891336521 in words is "one billion, eight hundred ninety-one million, three hundred thirty-six thousand, five hundred twenty-one".