81949452 has 72 divisors (see below), whose sum is σ = 219327696. Its totient is φ = 23721984.

The previous prime is 81949327. The next prime is 81949453. The reversal of 81949452 is 25494918.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (81949453) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33288 + ... + 35664.

It is an arithmetic number, because the mean of its divisors is an integer number (3046218).

Almost surely, 2^81949452 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81949452, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109663848).

81949452 is an abundant number, since it is smaller than the sum of its proper divisors (137378244).

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

81949452 is a wasteful number, since it uses less digits than its factorization.

81949452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2427 (or 2412 counting only the distinct ones).

The product of its digits is 103680, while the sum is 42.

The square root of 81949452 is about 9052.5936614873. The cubic root of 81949452 is about 434.3588599631.

The spelling of 81949452 in words is "eighty-one million, nine hundred forty-nine thousand, four hundred fifty-two".