691629681 has 8 divisors (see below), whose sum is σ = 929434624. Its totient is φ = 457455600.

The previous prime is 691629629. The next prime is 691629689. The reversal of 691629681 is 186926196.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 691629681 - 2¹⁰ = 691628657 is a prime.

It is a super-2 number, since 2×691629681² = 956703231280323522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 691629681.

It is not an unprimeable number, because it can be changed into a prime (691629689) 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, 907270 + ... + 908031.

It is an arithmetic number, because the mean of its divisors is an integer number (116179328).

Almost surely, 2^691629681 is an apocalyptic number.

It is an amenable number.

691629681 is a deficient number, since it is larger than the sum of its proper divisors (237804943).

691629681 is a wasteful number, since it uses less digits than its factorization.

691629681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1815431.

The product of its digits is 279936, while the sum is 48.

The square root of 691629681 is about 26298.8532259488. The cubic root of 691629681 is about 884.3507344930.

The spelling of 691629681 in words is "six hundred ninety-one million, six hundred twenty-nine thousand, six hundred eighty-one".