221101020 has 144 divisors (see below), whose sum is σ = 770165760. Its totient is φ = 50295168.

The previous prime is 221101007. The next prime is 221101039. The reversal of 221101020 is 20101122.

It is a super-2 number, since 2×221101020² = 97771322090080800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 221100993 and 221101011.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 477309 + ... + 477771.

Almost surely, 2^221101020 is an apocalyptic number.

221101020 is a gapful number since it is divisible by the number (20) 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 221101020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (385082880).

221101020 is an abundant number, since it is smaller than the sum of its proper divisors (549064740).

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

221101020 is a wasteful number, since it uses less digits than its factorization.

221101020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 864 (or 859 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 221101020 is about 14869.4660294175. The cubic root of 221101020 is about 604.6864664165.

Adding to 221101020 its reverse (20101122), we get a palindrome (241202142).

The spelling of 221101020 in words is "two hundred twenty-one million, one hundred one thousand, twenty".