81481901 has 8 divisors (see below), whose sum is σ = 86827320. Its totient is φ = 76197888.

The previous prime is 81481817. The next prime is 81481913. The reversal of 81481901 is 10918418.

It can be written as a sum of positive squares in 4 ways, for example, as 391876 + 81090025 = 626^2 + 9005^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81481901 - 2¹⁸ = 81219757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81481921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12596 + ... + 17933.

It is an arithmetic number, because the mean of its divisors is an integer number (10853415).

Almost surely, 2^81481901 is an apocalyptic number.

It is an amenable number.

81481901 is a deficient number, since it is larger than the sum of its proper divisors (5345419).

81481901 is a wasteful number, since it uses less digits than its factorization.

81481901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30703.

The product of its (nonzero) digits is 2304, while the sum is 32.

The square root of 81481901 is about 9026.7325760765. The cubic root of 81481901 is about 433.5312263128.

The spelling of 81481901 in words is "eighty-one million, four hundred eighty-one thousand, nine hundred one".