221429978 has 32 divisors (see below), whose sum is σ = 425305728. Its totient is φ = 83937600.

The previous prime is 221429977. The next prime is 221429987. The reversal of 221429978 is 879924122.

It is not an unprimeable number, because it can be changed into a prime (221429977) 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 15 ways as a sum of consecutive naturals, for example, 13733 + ... + 25128.

It is an arithmetic number, because the mean of its divisors is an integer number (13290804).

Almost surely, 2^221429978 is an apocalyptic number.

221429978 is a deficient number, since it is larger than the sum of its proper divisors (203875750).

221429978 is a wasteful number, since it uses less digits than its factorization.

221429978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38918.

The product of its digits is 145152, while the sum is 44.

The square root of 221429978 is about 14880.5234450943. The cubic root of 221429978 is about 604.9862055457.

The spelling of 221429978 in words is "two hundred twenty-one million, four hundred twenty-nine thousand, nine hundred seventy-eight".