29971840 has 32 divisors (see below), whose sum is σ = 71652960. Its totient is φ = 11988480.

The previous prime is 29971831. The next prime is 29971841. The reversal of 29971840 is 4817992.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×29971840² = 1796622385971200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 29971793 and 29971802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (29971841) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22776 + ... + 24055.

It is an arithmetic number, because the mean of its divisors is an integer number (2239155).

Almost surely, 2^29971840 is an apocalyptic number.

29971840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

29971840 is an abundant number, since it is smaller than the sum of its proper divisors (41681120).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

29971840 is an equidigital number, since it uses as much as digits as its factorization.

29971840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46850 (or 46838 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 29971840 is about 5474.6543269872. The cubic root of 29971840 is about 310.6259983072.

The spelling of 29971840 in words is "twenty-nine million, nine hundred seventy-one thousand, eight hundred forty".