221902401 has 16 divisors (see below), whose sum is σ = 340803584. Its totient is φ = 125801424.

The previous prime is 221902399. The next prime is 221902423. The reversal of 221902401 is 104209122.

It is not a de Polignac number, because 221902401 - 2¹ = 221902399 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221902301) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38935 + ... + 44268.

It is an arithmetic number, because the mean of its divisors is an integer number (21300224).

Almost surely, 2^221902401 is an apocalyptic number.

221902401 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

221902401 is a deficient number, since it is larger than the sum of its proper divisors (118901183).

221902401 is a wasteful number, since it uses less digits than its factorization.

221902401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83340.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 221902401 is about 14896.3888577064. The cubic root of 221902401 is about 605.4161479024.

The spelling of 221902401 in words is "two hundred twenty-one million, nine hundred two thousand, four hundred one".