221478100 has 36 divisors (see below), whose sum is σ = 490843584. Its totient is φ = 86704480.

The previous prime is 221478097. The next prime is 221478107. The reversal of 221478100 is 1874122.

It is a happy number.

It is a super-2 number, since 2×221478100² = 98105097559220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221478107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18862 + ... + 28261.

It is an arithmetic number, because the mean of its divisors is an integer number (13634544).

Almost surely, 2^221478100 is an apocalyptic number.

221478100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221478100 is an abundant number, since it is smaller than the sum of its proper divisors (269365484).

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

221478100 is a wasteful number, since it uses less digits than its factorization.

221478100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47184 (or 47177 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 221478100 is about 14882.1403030613. The cubic root of 221478100 is about 605.0300283345.

The spelling of 221478100 in words is "two hundred twenty-one million, four hundred seventy-eight thousand, one hundred".