81401857 has 4 divisors (see below), whose sum is σ = 81432000. Its totient is φ = 81371716.

The previous prime is 81401839. The next prime is 81401891. The reversal of 81401857 is 75810418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81401857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81401897) 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, 10573 + ... + 16570.

It is an arithmetic number, because the mean of its divisors is an integer number (20358000).

Almost surely, 2^81401857 is an apocalyptic number.

It is an amenable number.

81401857 is a deficient number, since it is larger than the sum of its proper divisors (30143).

81401857 is a wasteful number, since it uses less digits than its factorization.

81401857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30142.

The product of its (nonzero) digits is 8960, while the sum is 34.

The square root of 81401857 is about 9022.2977671988. The cubic root of 81401857 is about 433.3892195509.

The spelling of 81401857 in words is "eighty-one million, four hundred one thousand, eight hundred fifty-seven".