81564763 has 12 divisors (see below), whose sum is σ = 95288952. Its totient is φ = 69612480.

The previous prime is 81564757. The next prime is 81564781. The reversal of 81564763 is 36746518.

It is a happy number.

It is not a de Polignac number, because 81564763 - 2¹³ = 81556571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81564863) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8356 + ... + 15262.

It is an arithmetic number, because the mean of its divisors is an integer number (7940746).

Almost surely, 2^81564763 is an apocalyptic number.

81564763 is a deficient number, since it is larger than the sum of its proper divisors (13724189).

81564763 is a wasteful number, since it uses less digits than its factorization.

81564763 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7162 (or 7155 counting only the distinct ones).

The product of its digits is 120960, while the sum is 40.

The square root of 81564763 is about 9031.3212211725. The cubic root of 81564763 is about 433.6781345778.

The spelling of 81564763 in words is "eighty-one million, five hundred sixty-four thousand, seven hundred sixty-three".