81402538 has 8 divisors (see below), whose sum is σ = 139547232. Its totient is φ = 34886796.

The previous prime is 81402527. The next prime is 81402557. The reversal of 81402538 is 83520418.

It is a sphenic number, since it is the product of 3 distinct primes.

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 3 ways as a sum of consecutive naturals, for example, 2907220 + ... + 2907247.

It is an arithmetic number, because the mean of its divisors is an integer number (17443404).

Almost surely, 2^81402538 is an apocalyptic number.

81402538 is a deficient number, since it is larger than the sum of its proper divisors (58144694).

81402538 is a wasteful number, since it uses less digits than its factorization.

81402538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5814476.

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 81402538 is about 9022.3355069516. The cubic root of 81402538 is about 433.3904281115.

The spelling of 81402538 in words is "eighty-one million, four hundred two thousand, five hundred thirty-eight".