81401737 has 4 divisors (see below), whose sum is σ = 81419796. Its totient is φ = 81383680.

The previous prime is 81401707. The next prime is 81401741. The reversal of 81401737 is 73710418.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 73710418 = 2 ⋅36855209.

It can be written as a sum of positive squares in 2 ways, for example, as 36832761 + 44568976 = 6069^2 + 6676^2 .

It is a cyclic number.

It is not a de Polignac number, because 81401737 - 2⁷ = 81401609 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81401699 and 81401708.

It is not an unprimeable number, because it can be changed into a prime (81401707) by changing a digit.

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, 3993 + ... + 13369.

It is an arithmetic number, because the mean of its divisors is an integer number (20354949).

Almost surely, 2^81401737 is an apocalyptic number.

It is an amenable number.

81401737 is a deficient number, since it is larger than the sum of its proper divisors (18059).

81401737 is an equidigital number, since it uses as much as digits as its factorization.

81401737 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18058.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 81401737 is about 9022.2911170057. The cubic root of 81401737 is about 433.3890065879.

The spelling of 81401737 in words is "eighty-one million, four hundred one thousand, seven hundred thirty-seven".