81249801 has 4 divisors (see below), whose sum is σ = 108333072. Its totient is φ = 54166532.

The previous prime is 81249787. The next prime is 81249811. The reversal of 81249801 is 10894218.

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 not a de Polignac number, because 81249801 - 2¹⁰ = 81248777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81249811) 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, 13541631 + ... + 13541636.

It is an arithmetic number, because the mean of its divisors is an integer number (27083268).

Almost surely, 2^81249801 is an apocalyptic number.

It is an amenable number.

81249801 is a deficient number, since it is larger than the sum of its proper divisors (27083271).

81249801 is a wasteful number, since it uses less digits than its factorization.

81249801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27083270.

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 81249801 is about 9013.8671501193. The cubic root of 81249801 is about 433.1191990669.

The spelling of 81249801 in words is "eighty-one million, two hundred forty-nine thousand, eight hundred one".