29921661 has 24 divisors (see below), whose sum is σ = 53886144. Its totient is φ = 15543360.

The previous prime is 29921623. The next prime is 29921681. The reversal of 29921661 is 16612992.

It is not a de Polignac number, because 29921661 - 2¹⁰ = 29920637 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (29921681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20896 + ... + 22281.

It is an arithmetic number, because the mean of its divisors is an integer number (2245256).

Almost surely, 2^29921661 is an apocalyptic number.

29921661 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

29921661 is a deficient number, since it is larger than the sum of its proper divisors (23964483).

29921661 is a wasteful number, since it uses less digits than its factorization.

29921661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43201 (or 43198 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 29921661 is about 5470.0695608008. The cubic root of 29921661 is about 310.4525509577.

The spelling of 29921661 in words is "twenty-nine million, nine hundred twenty-one thousand, six hundred sixty-one".