221953836 has 96 divisors (see below), whose sum is σ = 596090880. Its totient is φ = 63673344.

The previous prime is 221953817. The next prime is 221953867. The reversal of 221953836 is 638359122.

It is a super-2 number, since 2×221953836² = 98527010630229792, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a junction number, because it is equal to n+sod(n) for n = 221953794 and 221953803.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 336475 + ... + 337133.

It is an arithmetic number, because the mean of its divisors is an integer number (6209280).

Almost surely, 2^221953836 is an apocalyptic number.

221953836 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221953836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (298045440).

221953836 is an abundant number, since it is smaller than the sum of its proper divisors (374137044).

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

221953836 is a wasteful number, since it uses less digits than its factorization.

221953836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 823 (or 821 counting only the distinct ones).

The product of its digits is 77760, while the sum is 39.

The square root of 221953836 is about 14898.1151828008. The cubic root of 221953836 is about 605.4629209789.

The spelling of 221953836 in words is "two hundred twenty-one million, nine hundred fifty-three thousand, eight hundred thirty-six".