19121997 has 8 divisors (see below), whose sum is σ = 26038656. Its totient is φ = 12476672.

The previous prime is 19121987. The next prime is 19122013. The reversal of 19121997 is 79912191.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19121997 - 2⁴ = 19121981 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19121987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67668 + ... + 67949.

It is an arithmetic number, because the mean of its divisors is an integer number (3254832).

Almost surely, 2^19121997 is an apocalyptic number.

It is an amenable number.

19121997 is a deficient number, since it is larger than the sum of its proper divisors (6916659).

19121997 is a wasteful number, since it uses less digits than its factorization.

19121997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135667.

The product of its digits is 10206, while the sum is 39.

The square root of 19121997 is about 4372.8705674877. The cubic root of 19121997 is about 267.4100643889.

The spelling of 19121997 in words is "nineteen million, one hundred twenty-one thousand, nine hundred ninety-seven".