81407400 has 192 divisors, whose sum is σ = 274238400. Its totient is φ = 19906560.

The previous prime is 81407377. The next prime is 81407423. The reversal of 81407400 is 470418.

It is an interprime number because it is at equal distance from previous prime (81407377) and next prime (81407423).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 421704 + ... + 421896.

It is an arithmetic number, because the mean of its divisors is an integer number (1428325).

Almost surely, 2^81407400 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 81407400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (137119200).

81407400 is an abundant number, since it is smaller than the sum of its proper divisors (192831000).

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

81407400 is a wasteful number, since it uses less digits than its factorization.

81407400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 259 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 81407400 is about 9022.6049453581. The cubic root of 81407400 is about 433.3990564350.

Adding to 81407400 its reverse (470418), we get a palindrome (81877818).

The spelling of 81407400 in words is "eighty-one million, four hundred seven thousand, four hundred".