168629721 has 24 divisors (see below), whose sum is σ = 254068416. Its totient is φ = 99253440.

The previous prime is 168629663. The next prime is 168629737. The reversal of 168629721 is 127926861.

It is not a de Polignac number, because 168629721 - 2¹⁹ = 168105433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (168629621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4431 + ... + 18891.

It is an arithmetic number, because the mean of its divisors is an integer number (10586184).

Almost surely, 2^168629721 is an apocalyptic number.

It is an amenable number.

168629721 is a deficient number, since it is larger than the sum of its proper divisors (85438695).

168629721 is a wasteful number, since it uses less digits than its factorization.

168629721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14513 (or 14500 counting only the distinct ones).

The product of its digits is 72576, while the sum is 42.

The square root of 168629721 is about 12985.7506906609. The cubic root of 168629721 is about 552.4734012570.

The spelling of 168629721 in words is "one hundred sixty-eight million, six hundred twenty-nine thousand, seven hundred twenty-one".