19971953 has 2 divisors, whose sum is σ = 19971954. Its totient is φ = 19971952.

The previous prime is 19971947. The next prime is 19971979. The reversal of 19971953 is 35917991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19254544 + 717409 = 4388^2 + 847^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19971953 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, 9985976 + 9985977.

It is an arithmetic number, because the mean of its divisors is an integer number (9985977).

Almost surely, 2^19971953 is an apocalyptic number.

It is an amenable number.

19971953 is a deficient number, since it is larger than the sum of its proper divisors (1).

19971953 is an equidigital number, since it uses as much as digits as its factorization.

19971953 is an evil number, because the sum of its binary digits is even.

The product of its digits is 76545, while the sum is 44.

The square root of 19971953 is about 4468.9991049451. Note that the first 3 decimals coincide. The cubic root of 19971953 is about 271.3148168491.

The spelling of 19971953 in words is "nineteen million, nine hundred seventy-one thousand, nine hundred fifty-three".