691047081 has 12 divisors (see below), whose sum is σ = 1050715120. Its totient is φ = 436450680.

The previous prime is 691047067. The next prime is 691047083. The reversal of 691047081 is 180740196.

It is not a de Polignac number, because 691047081 - 2⁷ = 691046953 is a prime.

It is a super-2 number, since 2×691047081² = 955092136317241122, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (691047083) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2020435 + ... + 2020776.

Almost surely, 2^691047081 is an apocalyptic number.

It is an amenable number.

691047081 is a deficient number, since it is larger than the sum of its proper divisors (359668039).

691047081 is a wasteful number, since it uses less digits than its factorization.

691047081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4041236 (or 4041233 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 36.

The square root of 691047081 is about 26287.7743637608. The cubic root of 691047081 is about 884.1023513446.

The spelling of 691047081 in words is "six hundred ninety-one million, forty-seven thousand, eighty-one".