81367740 has 60 divisors (see below), whose sum is σ = 255258696. Its totient is φ = 21697632.

The previous prime is 81367733. The next prime is 81367751. The reversal of 81367740 is 4776318.

It is a tau number, because it is divible by the number of its divisors (60).

It is a super-2 number, since 2×81367740² = 13241418225415200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 81367695 and 81367704.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 23494 + ... + 26733.

Almost surely, 2^81367740 is an apocalyptic number.

It is an amenable number.

81367740 is an abundant number, since it is smaller than the sum of its proper divisors (173890956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81367740 is a wasteful number, since it uses less digits than its factorization.

81367740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50248 (or 50237 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The square root of 81367740 is about 9020.4068644380. The cubic root of 81367740 is about 433.3286639865.

It can be divided in two parts, 8136 and 7740, that added together give a square (15876 = 126²).

The spelling of 81367740 in words is "eighty-one million, three hundred sixty-seven thousand, seven hundred forty".