81878755 has 12 divisors (see below), whose sum is σ = 114296400. Its totient is φ = 56145264.

The previous prime is 81878737. The next prime is 81878759. The reversal of 81878755 is 55787818.

It is not a de Polignac number, because 81878755 - 2⁹ = 81878243 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is a junction number, because it is equal to n+sod(n) for n = 81878699 and 81878708.

It is not an unprimeable number, because it can be changed into a prime (81878759) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 166855 + ... + 167344.

It is an arithmetic number, because the mean of its divisors is an integer number (9524700).

Almost surely, 2^81878755 is an apocalyptic number.

81878755 is a deficient number, since it is larger than the sum of its proper divisors (32417645).

81878755 is a wasteful number, since it uses less digits than its factorization.

81878755 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334218 (or 334211 counting only the distinct ones).

The product of its digits is 627200, while the sum is 49.

The square root of 81878755 is about 9048.6880264489. The cubic root of 81878755 is about 434.2339182977.

The spelling of 81878755 in words is "eighty-one million, eight hundred seventy-eight thousand, seven hundred fifty-five".