81783356940 has 48 divisors (see below), whose sum is σ = 254437112160. Its totient is φ = 21808895040.

The previous prime is 81783356939. The next prime is 81783356969. The reversal of 81783356940 is 4965338718.

81783356940 is a `hidden beast` number, since 8 + 1 + 7 + 8 + 33 + 569 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75724791 + ... + 75725870.

It is an arithmetic number, because the mean of its divisors is an integer number (5300773170).

Almost surely, 2^81783356940 is an apocalyptic number.

It is an amenable number.

81783356940 is an abundant number, since it is smaller than the sum of its proper divisors (172653755220).

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

81783356940 is a wasteful number, since it uses less digits than its factorization.

81783356940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151450679 (or 151450671 counting only the distinct ones).

The product of its (nonzero) digits is 4354560, while the sum is 54.

The spelling of 81783356940 in words is "eighty-one billion, seven hundred eighty-three million, three hundred fifty-six thousand, nine hundred forty".