81207740 has 12 divisors (see below), whose sum is σ = 170536296. Its totient is φ = 32483088.

The previous prime is 81207739. The next prime is 81207761. The reversal of 81207740 is 4770218.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2030174 + ... + 2030213.

It is an arithmetic number, because the mean of its divisors is an integer number (14211358).

Almost surely, 2^81207740 is an apocalyptic number.

It is an amenable number.

81207740 is an abundant number, since it is smaller than the sum of its proper divisors (89328556).

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

81207740 is a wasteful number, since it uses less digits than its factorization.

81207740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4060396 (or 4060394 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 29.

The square root of 81207740 is about 9011.5337207381. The cubic root of 81207740 is about 433.0444478229.

Adding to 81207740 its reverse (4770218), we get a palindrome (85977958).

The spelling of 81207740 in words is "eighty-one million, two hundred seven thousand, seven hundred forty".