3691899121 has 3 divisors (see below), whose sum is σ = 3691959883. Its totient is φ = 3691838360.

The previous prime is 3691899091. The next prime is 3691899137. The reversal of 3691899121 is 1219981963.

The square root of 3691899121 is 60761.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1219981963 = 19 ⋅64209577.

It can be written as a sum of positive squares in only one way, i.e., 3400172721 + 291726400 = 58311^2 + 17080^2 .

It is not a de Polignac number, because 3691899121 - 2¹¹ = 3691897073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3691899521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 30381 + ... + 91141.

Almost surely, 2^3691899121 is an apocalyptic number.

3691899121 is the 60761-st square number.

3691899121 is the 30381-st centered octagonal number.

It is an amenable number.

3691899121 is a deficient number, since it is larger than the sum of its proper divisors (60762).

3691899121 is an frugal number, since it uses more digits than its factorization.

3691899121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121522 (or 60761 counting only the distinct ones).

The product of its digits is 209952, while the sum is 49.

The cubic root of 3691899121 is about 1545.5507678425.

Multiplying 3691899121 by its sum of digits (49), we get a square (180903056929 = 425327²).

The spelling of 3691899121 in words is "three billion, six hundred ninety-one million, eight hundred ninety-nine thousand, one hundred twenty-one".