81225977 has 6 divisors (see below), whose sum is σ = 94487418. Its totient is φ = 69622224.

The previous prime is 81225973. The next prime is 81226001. The reversal of 81225977 is 77952218.

It can be written as a sum of positive squares in only one way, i.e., 67305616 + 13920361 = 8204^2 + 3731^2 .

It is not a de Polignac number, because 81225977 - 2² = 81225973 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81225973) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 828788 + ... + 828885.

It is an arithmetic number, because the mean of its divisors is an integer number (15747903).

Almost surely, 2^81225977 is an apocalyptic number.

It is an amenable number.

81225977 is a deficient number, since it is larger than the sum of its proper divisors (13261441).

81225977 is a wasteful number, since it uses less digits than its factorization.

81225977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1657687 (or 1657680 counting only the distinct ones).

The product of its digits is 70560, while the sum is 41.

The square root of 81225977 is about 9012.5455338656. The cubic root of 81225977 is about 433.0768619765.

The spelling of 81225977 in words is "eighty-one million, two hundred twenty-five thousand, nine hundred seventy-seven".