81999753 has 16 divisors (see below), whose sum is σ = 122048256. Its totient is φ = 48540240.

The previous prime is 81999739. The next prime is 81999769. The reversal of 81999753 is 35799918.

It is a happy number.

It is not a de Polignac number, because 81999753 - 2⁴ = 81999737 is a prime.

It is a super-2 number, since 2×81999753² = 13447918984122018, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81999696 and 81999705.

It is not an unprimeable number, because it can be changed into a prime (81999703) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27475 + ... + 30312.

It is an arithmetic number, because the mean of its divisors is an integer number (7628016).

Almost surely, 2^81999753 is an apocalyptic number.

It is an amenable number.

81999753 is a deficient number, since it is larger than the sum of its proper divisors (40048503).

81999753 is a wasteful number, since it uses less digits than its factorization.

81999753 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57844.

The product of its digits is 612360, while the sum is 51.

The square root of 81999753 is about 9055.3714998337. The cubic root of 81999753 is about 434.4477123622.

The spelling of 81999753 in words is "eighty-one million, nine hundred ninety-nine thousand, seven hundred fifty-three".