29691681 has 4 divisors (see below), whose sum is σ = 39588912. Its totient is φ = 19794452.

The previous prime is 29691671. The next prime is 29691721. The reversal of 29691681 is 18619692.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 29691681 - 2⁶ = 29691617 is a prime.

It is a super-2 number, since 2×29691681² = 1763191841211522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (29691611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4948611 + ... + 4948616.

It is an arithmetic number, because the mean of its divisors is an integer number (9897228).

Almost surely, 2^29691681 is an apocalyptic number.

It is an amenable number.

29691681 is a deficient number, since it is larger than the sum of its proper divisors (9897231).

29691681 is an equidigital number, since it uses as much as digits as its factorization.

29691681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9897230.

The product of its digits is 46656, while the sum is 42.

The square root of 29691681 is about 5449.0073407915. The cubic root of 29691681 is about 309.6551176665.

The spelling of 29691681 in words is "twenty-nine million, six hundred ninety-one thousand, six hundred eighty-one".