19972191 has 8 divisors (see below), whose sum is σ = 26670384. Its totient is φ = 13294400.

The previous prime is 19972181. The next prime is 19972201. The reversal of 19972191 is 19127991.

It is an interprime number because it is at equal distance from previous prime (19972181) and next prime (19972201).

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 19972191 - 2⁷ = 19972063 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19972111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2646 + ... + 6851.

It is an arithmetic number, because the mean of its divisors is an integer number (3333798).

Almost surely, 2^19972191 is an apocalyptic number.

19972191 is a deficient number, since it is larger than the sum of its proper divisors (6698193).

19972191 is an equidigital number, since it uses as much as digits as its factorization.

19972191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10201.

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

The square root of 19972191 is about 4469.0257327521. The cubic root of 19972191 is about 271.3158945717.

It can be divided in two parts, 199 and 72191, that added together give a triangular number (72390 = T₃₈₀).

The spelling of 19972191 in words is "nineteen million, nine hundred seventy-two thousand, one hundred ninety-one".