81428741 has 4 divisors (see below), whose sum is σ = 81685932. Its totient is φ = 81171552.

The previous prime is 81428731. The next prime is 81428761. The reversal of 81428741 is 14782418.

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 13432225 + 67996516 = 3665^2 + 8246^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81428741 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 (81428731) 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, 128120 + ... + 128753.

It is an arithmetic number, because the mean of its divisors is an integer number (20421483).

Almost surely, 2^81428741 is an apocalyptic number.

It is an amenable number.

81428741 is a deficient number, since it is larger than the sum of its proper divisors (257191).

81428741 is a wasteful number, since it uses less digits than its factorization.

81428741 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257190.

The product of its digits is 14336, while the sum is 35.

The square root of 81428741 is about 9023.7875085798. The cubic root of 81428741 is about 433.4369250692.

The spelling of 81428741 in words is "eighty-one million, four hundred twenty-eight thousand, seven hundred forty-one".