81401079 has 4 divisors (see below), whose sum is σ = 108534776. Its totient is φ = 54267384.

The previous prime is 81401069. The next prime is 81401081. The reversal of 81401079 is 97010418.

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

It is not a de Polignac number, because 81401079 - 2⁴ = 81401063 is a prime.

It is a super-2 number, since 2×81401079² = 13252271324728482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81401029) 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, 13566844 + ... + 13566849.

It is an arithmetic number, because the mean of its divisors is an integer number (27133694).

Almost surely, 2^81401079 is an apocalyptic number.

81401079 is a deficient number, since it is larger than the sum of its proper divisors (27133697).

81401079 is a wasteful number, since it uses less digits than its factorization.

81401079 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27133696.

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 81401079 is about 9022.2546516932. The cubic root of 81401079 is about 433.3878388375.

The spelling of 81401079 in words is "eighty-one million, four hundred one thousand, seventy-nine".