81140477 has 4 divisors (see below), whose sum is σ = 88516896. Its totient is φ = 73764060.

The previous prime is 81140467. The next prime is 81140537. The reversal of 81140477 is 77404118.

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 81140477 - 2⁴ = 81140461 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 (81140447) 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, 3688193 + ... + 3688214.

It is an arithmetic number, because the mean of its divisors is an integer number (22129224).

Almost surely, 2^81140477 is an apocalyptic number.

It is an amenable number.

81140477 is a deficient number, since it is larger than the sum of its proper divisors (7376419).

81140477 is a wasteful number, since it uses less digits than its factorization.

81140477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7376418.

The product of its (nonzero) digits is 6272, while the sum is 32.

The square root of 81140477 is about 9007.8008970003. The cubic root of 81140477 is about 432.9248536625.

The spelling of 81140477 in words is "eighty-one million, one hundred forty thousand, four hundred seventy-seven".