691000078 has 16 divisors (see below), whose sum is σ = 1054911744. Its totient is φ = 339391800.

The previous prime is 691000073. The next prime is 691000091. The reversal of 691000078 is 870000196.

It is a super-2 number, since 2×691000078² = 954962215592012168, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691000073) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42153 + ... + 56203.

It is an arithmetic number, because the mean of its divisors is an integer number (65931984).

Almost surely, 2^691000078 is an apocalyptic number.

691000078 is a deficient number, since it is larger than the sum of its proper divisors (363911666).

691000078 is a wasteful number, since it uses less digits than its factorization.

691000078 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14487.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 691000078 is about 26286.8803398197. The cubic root of 691000078 is about 884.0823062053.

The spelling of 691000078 in words is "six hundred ninety-one million, seventy-eight", and thus it is an aban number.