19971947 has 2 divisors, whose sum is σ = 19971948. Its totient is φ = 19971946.

The previous prime is 19971943. The next prime is 19971953. The reversal of 19971947 is 74917991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19971947 - 2² = 19971943 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (19971943) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9985973 + 9985974.

It is an arithmetic number, because the mean of its divisors is an integer number (9985974).

Almost surely, 2^19971947 is an apocalyptic number.

19971947 is a deficient number, since it is larger than the sum of its proper divisors (1).

19971947 is an equidigital number, since it uses as much as digits as its factorization.

19971947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 142884, while the sum is 47.

The square root of 19971947 is about 4468.9984336538. The cubic root of 19971947 is about 271.3147896796.

The spelling of 19971947 in words is "nineteen million, nine hundred seventy-one thousand, nine hundred forty-seven".