81123124 has 6 divisors (see below), whose sum is σ = 141965474. Its totient is φ = 40561560.

The previous prime is 81123113. The next prime is 81123127. The reversal of 81123124 is 42132118.

81123124 = 1827² + 1828² + ... + 1850².

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 68591524 + 12531600 = 8282^2 + 3540^2 .

It is a super-2 number, since 2×81123124² = 13161922495038752, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81123095 and 81123104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81123127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10140387 + ... + 10140394.

Almost surely, 2^81123124 is an apocalyptic number.

It is an amenable number.

81123124 is a deficient number, since it is larger than the sum of its proper divisors (60842350).

81123124 is a wasteful number, since it uses less digits than its factorization.

81123124 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20280785 (or 20280783 counting only the distinct ones).

The product of its digits is 384, while the sum is 22.

The square root of 81123124 is about 9006.8376248270. The cubic root of 81123124 is about 432.8939891632.

It can be divided in two parts, 8112 and 3124, that added together give a square (11236 = 106²).

The spelling of 81123124 in words is "eighty-one million, one hundred twenty-three thousand, one hundred twenty-four".