81778052 has 18 divisors (see below), whose sum is σ = 151042878. Its totient is φ = 38736288.

The previous prime is 81778051. The next prime is 81778061. The reversal of 81778052 is 25087718.

It can be written as a sum of positive squares in only one way, i.e., 77721856 + 4056196 = 8816^2 + 2014^2 .

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a junction number, because it is equal to n+sod(n) for n = 81777997 and 81778015.

It is not an unprimeable number, because it can be changed into a prime (81778051) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 26873 + ... + 29760.

It is an arithmetic number, because the mean of its divisors is an integer number (8391271).

Almost surely, 2^81778052 is an apocalyptic number.

It is an amenable number.

81778052 is a deficient number, since it is larger than the sum of its proper divisors (69264826).

81778052 is a wasteful number, since it uses less digits than its factorization.

81778052 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56675 (or 56654 counting only the distinct ones).

The product of its (nonzero) digits is 31360, while the sum is 38.

The square root of 81778052 is about 9043.1218061021. The cubic root of 81778052 is about 434.0558232681.

The spelling of 81778052 in words is "eighty-one million, seven hundred seventy-eight thousand, fifty-two".