81201047 has 4 divisors (see below), whose sum is σ = 81221280. Its totient is φ = 81180816.

The previous prime is 81200963. The next prime is 81201049. The reversal of 81201047 is 74010218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74010218 = 2 ⋅37005109.

It is a cyclic number.

It is not a de Polignac number, because 81201047 - 2¹⁰ = 81200023 is a prime.

It is a super-2 number, since 2×81201047² = 13187220067792418, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81201049) 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, 1838 + ... + 12875.

It is an arithmetic number, because the mean of its divisors is an integer number (20305320).

Almost surely, 2^81201047 is an apocalyptic number.

81201047 is a deficient number, since it is larger than the sum of its proper divisors (20233).

81201047 is a wasteful number, since it uses less digits than its factorization.

81201047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20232.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 81201047 is about 9011.1623556565. The cubic root of 81201047 is about 433.0325505739.

The spelling of 81201047 in words is "eighty-one million, two hundred one thousand, forty-seven".