68721906 has 16 divisors (see below), whose sum is σ = 149938848. Its totient is φ = 20824800.

The previous prime is 68721847. The next prime is 68721923. The reversal of 68721906 is 60912786.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 520555 + ... + 520686.

It is an arithmetic number, because the mean of its divisors is an integer number (9371178).

Almost surely, 2^68721906 is an apocalyptic number.

68721906 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

68721906 is an abundant number, since it is smaller than the sum of its proper divisors (81216942).

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

68721906 is a wasteful number, since it uses less digits than its factorization.

68721906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1041257.

The product of its (nonzero) digits is 36288, while the sum is 39.

The square root of 68721906 is about 8289.8676708377. The cubic root of 68721906 is about 409.6048264571.

It can be divided in two parts, 6872 and 1906, that added together give a palindrome (8778).

The spelling of 68721906 in words is "sixty-eight million, seven hundred twenty-one thousand, nine hundred six".