18971959 has 2 divisors, whose sum is σ = 18971960. Its totient is φ = 18971958.

The previous prime is 18971947. The next prime is 18971993. The reversal of 18971959 is 95917981.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18971959 - 2⁷ = 18971831 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18971059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9485979 + 9485980.

It is an arithmetic number, because the mean of its divisors is an integer number (9485980).

Almost surely, 2^18971959 is an apocalyptic number.

18971959 is a deficient number, since it is larger than the sum of its proper divisors (1).

18971959 is an equidigital number, since it uses as much as digits as its factorization.

18971959 is an evil number, because the sum of its binary digits is even.

The product of its digits is 204120, while the sum is 49.

The square root of 18971959 is about 4355.6812325973. The cubic root of 18971959 is about 266.7088289237.

The spelling of 18971959 in words is "eighteen million, nine hundred seventy-one thousand, nine hundred fifty-nine".