221422640 has 40 divisors (see below), whose sum is σ = 525769920. Its totient is φ = 86683136.

The previous prime is 221422639. The next prime is 221422657. The reversal of 221422640 is 46224122.

It is a tau number, because it is divible by the number of its divisors (40).

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 7 ways as a sum of consecutive naturals, for example, 25685 + ... + 33204.

It is an arithmetic number, because the mean of its divisors is an integer number (13144248).

Almost surely, 2^221422640 is an apocalyptic number.

221422640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221422640 is an abundant number, since it is smaller than the sum of its proper divisors (304347280).

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

221422640 is a wasteful number, since it uses less digits than its factorization.

221422640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58949 (or 58943 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 23.

The square root of 221422640 is about 14880.2768791444. The cubic root of 221422640 is about 604.9795225635.

Adding to 221422640 its reverse (46224122), we get a palindrome (267646762).

The spelling of 221422640 in words is "two hundred twenty-one million, four hundred twenty-two thousand, six hundred forty".