81401438 has 4 divisors (see below), whose sum is σ = 122102160. Its totient is φ = 40700718.

The previous prime is 81401431. The next prime is 81401459. The reversal of 81401438 is 83410418.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 81401438.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81401431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20350358 + ... + 20350361.

It is an arithmetic number, because the mean of its divisors is an integer number (30525540).

Almost surely, 2^81401438 is an apocalyptic number.

81401438 is a deficient number, since it is larger than the sum of its proper divisors (40700722).

81401438 is a wasteful number, since it uses less digits than its factorization.

81401438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40700721.

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 81401438 is about 9022.2745469200. The cubic root of 81401438 is about 433.3884759544.

The spelling of 81401438 in words is "eighty-one million, four hundred one thousand, four hundred thirty-eight".