19797971 has 4 divisors (see below), whose sum is σ = 19807152. Its totient is φ = 19788792.

The previous prime is 19797959. The next prime is 19797983. The reversal of 19797971 is 17979791.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (19797959) and next prime (19797983).

It is a cyclic number.

It is not a de Polignac number, because 19797971 - 2¹⁰ = 19796947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19797901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 605 + ... + 6321.

It is an arithmetic number, because the mean of its divisors is an integer number (4951788).

Almost surely, 2^19797971 is an apocalyptic number.

19797971 is a deficient number, since it is larger than the sum of its proper divisors (9181).

19797971 is an equidigital number, since it uses as much as digits as its factorization.

19797971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9180.

The product of its digits is 250047, while the sum is 50.

The square root of 19797971 is about 4449.4910944961. The cubic root of 19797971 is about 270.5246816187.

The spelling of 19797971 in words is "nineteen million, seven hundred ninety-seven thousand, nine hundred seventy-one".