221020401 has 8 divisors (see below), whose sum is σ = 336793024. Its totient is φ = 126297360.

The previous prime is 221020399. The next prime is 221020403. The reversal of 221020401 is 104020122.

It is an interprime number because it is at equal distance from previous prime (221020399) and next prime (221020403).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 221020401 - 2¹ = 221020399 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221020403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5262370 + ... + 5262411.

It is an arithmetic number, because the mean of its divisors is an integer number (42099128).

Almost surely, 2^221020401 is an apocalyptic number.

221020401 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

221020401 is a deficient number, since it is larger than the sum of its proper divisors (115772623).

221020401 is a wasteful number, since it uses less digits than its factorization.

221020401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10524791.

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 221020401 is about 14866.7548913675. The cubic root of 221020401 is about 604.6129628441.

Adding to 221020401 its reverse (104020122), we get a palindrome (325040523).

The spelling of 221020401 in words is "two hundred twenty-one million, twenty thousand, four hundred one".