221072420 has 24 divisors (see below), whose sum is σ = 491561784. Its totient is φ = 83227136.

The previous prime is 221072419. The next prime is 221072473. The reversal of 221072420 is 24270122.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 31899904 + 189172516 = 5648^2 + 13754^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 221072392 and 221072401.

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, 324767 + ... + 325446.

It is an arithmetic number, because the mean of its divisors is an integer number (20481741).

Almost surely, 2^221072420 is an apocalyptic number.

221072420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221072420 is an abundant number, since it is smaller than the sum of its proper divisors (270489364).

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

221072420 is a wasteful number, since it uses less digits than its factorization.

221072420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 650239 (or 650237 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 221072420 is about 14868.5042959943. The cubic root of 221072420 is about 604.6603926959.

The spelling of 221072420 in words is "two hundred twenty-one million, seventy-two thousand, four hundred twenty".