221491420 has 12 divisors (see below), whose sum is σ = 465132024. Its totient is φ = 88596560.

The previous prime is 221491397. The next prime is 221491423. The reversal of 221491420 is 24194122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221491423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5537266 + ... + 5537305.

It is an arithmetic number, because the mean of its divisors is an integer number (38761002).

Almost surely, 2^221491420 is an apocalyptic number.

221491420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221491420 is an abundant number, since it is smaller than the sum of its proper divisors (243640604).

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

221491420 is a wasteful number, since it uses less digits than its factorization.

221491420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11074580 (or 11074578 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 221491420 is about 14882.5878126084. The cubic root of 221491420 is about 605.0421572062.

The spelling of 221491420 in words is "two hundred twenty-one million, four hundred ninety-one thousand, four hundred twenty".