221553840 has 40 divisors (see below), whose sum is σ = 686817648. Its totient is φ = 59080960.

The previous prime is 221553821. The next prime is 221553853. The reversal of 221553840 is 48355122.

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

It is a super-2 number, since 2×221553840² = 98172208037491200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 221553798 and 221553807.

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, 461331 + ... + 461810.

Almost surely, 2^221553840 is an apocalyptic number.

221553840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221553840 is an abundant number, since it is smaller than the sum of its proper divisors (465263808).

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

221553840 is a wasteful number, since it uses less digits than its factorization.

221553840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 923157 (or 923151 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

The square root of 221553840 is about 14884.6847464096. The cubic root of 221553840 is about 605.0989888798.

The spelling of 221553840 in words is "two hundred twenty-one million, five hundred fifty-three thousand, eight hundred forty".