81340157 has 4 divisors (see below), whose sum is σ = 84145020. Its totient is φ = 78535296.

The previous prime is 81340153. The next prime is 81340163. The reversal of 81340157 is 75104318.

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

It can be written as a sum of positive squares in 2 ways, for example, as 54081316 + 27258841 = 7354^2 + 5221^2 .

It is a cyclic number.

It is not a de Polignac number, because 81340157 - 2² = 81340153 is a prime.

It is a super-2 number, since 2×81340157² = 13232442281569298, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 2804833 = 81340157 / (8 + 1 + 3 + 4 + 0 + 1 + 5 + 7).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81340153) 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, 1402388 + ... + 1402445.

It is an arithmetic number, because the mean of its divisors is an integer number (21036255).

Almost surely, 2^81340157 is an apocalyptic number.

It is an amenable number.

81340157 is a deficient number, since it is larger than the sum of its proper divisors (2804863).

81340157 is a wasteful number, since it uses less digits than its factorization.

81340157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2804862.

The product of its (nonzero) digits is 3360, while the sum is 29.

The square root of 81340157 is about 9018.8778126771. The cubic root of 81340157 is about 433.2796934920.

The spelling of 81340157 in words is "eighty-one million, three hundred forty thousand, one hundred fifty-seven".