29978991 has 40 divisors (see below), whose sum is σ = 52601120. Its totient is φ = 16656192.

The previous prime is 29978981. The next prime is 29979029. The reversal of 29978991 is 19987992.

It is not a de Polignac number, because 29978991 - 2⁷ = 29978863 is a prime.

It is a Duffinian number.

29978991 is a modest number, since divided by 8991 gives 2997 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (29978911) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 20265 + ... + 21693.

It is an arithmetic number, because the mean of its divisors is an integer number (1315028).

Almost surely, 2^29978991 is an apocalyptic number.

29978991 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

29978991 is a deficient number, since it is larger than the sum of its proper divisors (22622129).

29978991 is a wasteful number, since it uses less digits than its factorization.

29978991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1485 (or 1476 counting only the distinct ones).

The product of its digits is 734832, while the sum is 54.

The square root of 29978991 is about 5475.3073886313. The cubic root of 29978991 is about 310.6507004930.

Subtracting from 29978991 its reverse (19987992), we obtain a palindrome (9990999).

The spelling of 29978991 in words is "twenty-nine million, nine hundred seventy-eight thousand, nine hundred ninety-one".