19927997 has 2 divisors, whose sum is σ = 19927998. Its totient is φ = 19927996.

The previous prime is 19927993. The next prime is 19928023. The reversal of 19927997 is 79972991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10106041 + 9821956 = 3179^2 + 3134^2 .

It is a cyclic number.

It is not a de Polignac number, because 19927997 - 2² = 19927993 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19927991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9963998 + 9963999.

It is an arithmetic number, because the mean of its divisors is an integer number (9963999).

Almost surely, 2^19927997 is an apocalyptic number.

It is an amenable number.

19927997 is a deficient number, since it is larger than the sum of its proper divisors (1).

19927997 is an equidigital number, since it uses as much as digits as its factorization.

19927997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 642978, while the sum is 53.

The square root of 19927997 is about 4464.0785163346. The cubic root of 19927997 is about 271.1156262810.

The spelling of 19927997 in words is "nineteen million, nine hundred twenty-seven thousand, nine hundred ninety-seven".