12191900 has 36 divisors (see below), whose sum is σ = 30237648. Its totient is φ = 4179840.

The previous prime is 12191899. The next prime is 12191903. The reversal of 12191900 is 919121.

It is a super-2 number, since 2×12191900² = 297284851220000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12191903) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8009 + ... + 9408.

Almost surely, 2^12191900 is an apocalyptic number.

12191900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

12191900 is an abundant number, since it is smaller than the sum of its proper divisors (18045748).

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

12191900 is a wasteful number, since it uses less digits than its factorization.

12191900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17438 (or 17431 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 12191900 is about 3491.6901351638. The cubic root of 12191900 is about 230.1567928997.

The spelling of 12191900 in words is "twelve million, one hundred ninety-one thousand, nine hundred".