71778906 has 32 divisors (see below), whose sum is σ = 166446720. Its totient is φ = 22885632.

The previous prime is 71778887. The next prime is 71778923. The reversal of 71778906 is 60987717.

It is a happy number.

It is a super-2 number, since 2×71778906² = 10304422693113672, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27655 + ... + 30138.

It is an arithmetic number, because the mean of its divisors is an integer number (5201460).

Almost surely, 2^71778906 is an apocalyptic number.

71778906 is an abundant number, since it is smaller than the sum of its proper divisors (94667814).

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

71778906 is a wasteful number, since it uses less digits than its factorization.

71778906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57827 (or 57821 counting only the distinct ones).

The product of its (nonzero) digits is 148176, while the sum is 45.

The square root of 71778906 is about 8472.2432684620. The cubic root of 71778906 is about 415.5905001684.

The spelling of 71778906 in words is "seventy-one million, seven hundred seventy-eight thousand, nine hundred six".