378991687 has 2 divisors, whose sum is σ = 378991688. Its totient is φ = 378991686.

The previous prime is 378991649. The next prime is 378991699. The reversal of 378991687 is 786199873.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 378991687 - 2¹⁵ = 378958919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (378994687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 189495843 + 189495844.

It is an arithmetic number, because the mean of its divisors is an integer number (189495844).

Almost surely, 2^378991687 is an apocalyptic number.

378991687 is a deficient number, since it is larger than the sum of its proper divisors (1).

378991687 is an equidigital number, since it uses as much as digits as its factorization.

378991687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4572288, while the sum is 58.

The square root of 378991687 is about 19467.7088276972. The cubic root of 378991687 is about 723.6744304790.

The spelling of 378991687 in words is "three hundred seventy-eight million, nine hundred ninety-one thousand, six hundred eighty-seven".