81200077 has 4 divisors (see below), whose sum is σ = 92800096. Its totient is φ = 69600060.

The previous prime is 81200059. The next prime is 81200113. The reversal of 81200077 is 77000218.

It is a happy number.

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 81200077 - 2¹⁵ = 81167309 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 (81200677) 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, 5799999 + ... + 5800012.

It is an arithmetic number, because the mean of its divisors is an integer number (23200024).

Almost surely, 2^81200077 is an apocalyptic number.

It is an amenable number.

81200077 is a deficient number, since it is larger than the sum of its proper divisors (11600019).

81200077 is a wasteful number, since it uses less digits than its factorization.

81200077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11600018.

The product of its (nonzero) digits is 784, while the sum is 25.

The square root of 81200077 is about 9011.1085333604. The cubic root of 81200077 is about 433.0308262806.

The spelling of 81200077 in words is "eighty-one million, two hundred thousand, seventy-seven".