19972121 has 8 divisors (see below), whose sum is σ = 21552384. Its totient is φ = 18398160.

The previous prime is 19972111. The next prime is 19972151. The reversal of 19972121 is 12127991.

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 19972121 - 2¹⁴ = 19955737 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19972111) 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, 6626 + ... + 9156.

It is an arithmetic number, because the mean of its divisors is an integer number (2694048).

Almost surely, 2^19972121 is an apocalyptic number.

It is an amenable number.

19972121 is a deficient number, since it is larger than the sum of its proper divisors (1580263).

19972121 is a wasteful number, since it uses less digits than its factorization.

19972121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3151.

The product of its digits is 2268, while the sum is 32.

The square root of 19972121 is about 4469.0179010606. The cubic root of 19972121 is about 271.3155775953.

The spelling of 19972121 in words is "nineteen million, nine hundred seventy-two thousand, one hundred twenty-one".