1897921836 has 36 divisors (see below), whose sum is σ = 4824046864. Its totient is φ = 629143200.

The previous prime is 1897921813. The next prime is 1897921841. The reversal of 1897921836 is 6381297981.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×1897921836² = 7204214591131221792, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 139120 + ... + 152151.

Almost surely, 2^1897921836 is an apocalyptic number.

It is an amenable number.

1897921836 is an abundant number, since it is smaller than the sum of its proper divisors (2926125028).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1897921836 is a wasteful number, since it uses less digits than its factorization.

1897921836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291462 (or 291457 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 54.

The square root of 1897921836 is about 43565.1447375078. The cubic root of 1897921836 is about 1238.1105972359.

The spelling of 1897921836 in words is "one billion, eight hundred ninety-seven million, nine hundred twenty-one thousand, eight hundred thirty-six".