1878861997 has 2 divisors, whose sum is σ = 1878861998. Its totient is φ = 1878861996.

The previous prime is 1878861991. The next prime is 1878862033. The reversal of 1878861997 is 7991688781.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1032401161 + 846460836 = 32131^2 + 29094^2 .

It is a cyclic number.

It is not a de Polignac number, because 1878861997 - 2²³ = 1870473389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1878861991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 939430998 + 939430999.

It is an arithmetic number, because the mean of its divisors is an integer number (939430999).

Almost surely, 2^1878861997 is an apocalyptic number.

It is an amenable number.

1878861997 is a deficient number, since it is larger than the sum of its proper divisors (1).

1878861997 is an equidigital number, since it uses as much as digits as its factorization.

1878861997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12192768, while the sum is 64.

The square root of 1878861997 is about 43345.8417498149. The cubic root of 1878861997 is about 1233.9520791028.

The spelling of 1878861997 in words is "one billion, eight hundred seventy-eight million, eight hundred sixty-one thousand, nine hundred ninety-seven".