394947891 has 24 divisors (see below), whose sum is σ = 625964976. Its totient is φ = 238455360.

The previous prime is 394947877. The next prime is 394947929. The reversal of 394947891 is 198749493.

394947891 = T₃₈₃₄ + T₃₈₃₅ + ... + T₃₈₈₆.

It is not a de Polignac number, because 394947891 - 2¹⁵ = 394915123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (394947821) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25645 + ... + 38046.

It is an arithmetic number, because the mean of its divisors is an integer number (26081874).

Almost surely, 2^394947891 is an apocalyptic number.

394947891 is a deficient number, since it is larger than the sum of its proper divisors (231017085).

394947891 is a wasteful number, since it uses less digits than its factorization.

394947891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63763 (or 63760 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 54.

The square root of 394947891 is about 19873.2959269468. The cubic root of 394947891 is about 733.6911260706.

The spelling of 394947891 in words is "three hundred ninety-four million, nine hundred forty-seven thousand, eight hundred ninety-one".