81321701 has 4 divisors (see below), whose sum is σ = 81389100. Its totient is φ = 81254304.

The previous prime is 81321697. The next prime is 81321743. The reversal of 81321701 is 10712318.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10712318 = 2 ⋅5356159.

It can be written as a sum of positive squares in 2 ways, for example, as 65529025 + 15792676 = 8095^2 + 3974^2 .

It is a cyclic number.

It is not a de Polignac number, because 81321701 - 2² = 81321697 is a prime.

It is a super-2 number, since 2×81321701² = 13226438107066802, 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 (81321791) 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, 31856 + ... + 34313.

It is an arithmetic number, because the mean of its divisors is an integer number (20347275).

Almost surely, 2^81321701 is an apocalyptic number.

It is an amenable number.

81321701 is a deficient number, since it is larger than the sum of its proper divisors (67399).

81321701 is a wasteful number, since it uses less digits than its factorization.

81321701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67398.

The product of its (nonzero) digits is 336, while the sum is 23.

The square root of 81321701 is about 9017.8545674678. The cubic root of 81321701 is about 433.2469207706.

The spelling of 81321701 in words is "eighty-one million, three hundred twenty-one thousand, seven hundred one".