19972397 has 8 divisors (see below), whose sum is σ = 20374200. Its totient is φ = 19574784.

The previous prime is 19972369. The next prime is 19972423. The reversal of 19972397 is 79327991.

It can be written as a sum of positive squares in 4 ways, for example, as 3924361 + 16048036 = 1981^2 + 4006^2 .

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 19972397 - 2¹⁰ = 19971373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19971397) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9629 + ... + 11517.

It is an arithmetic number, because the mean of its divisors is an integer number (2546775).

Almost surely, 2^19972397 is an apocalyptic number.

It is an amenable number.

19972397 is a deficient number, since it is larger than the sum of its proper divisors (401803).

19972397 is a wasteful number, since it uses less digits than its factorization.

19972397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2095.

The product of its digits is 214326, while the sum is 47.

The square root of 19972397 is about 4469.0487802216. The cubic root of 19972397 is about 271.3168273834.

The spelling of 19972397 in words is "nineteen million, nine hundred seventy-two thousand, three hundred ninety-seven".