221401901 has 4 divisors (see below), whose sum is σ = 253030752. Its totient is φ = 189773052.

The previous prime is 221401853. The next prime is 221401903. The reversal of 221401901 is 109104122.

221401901 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 109104122 = 2 ⋅54552061.

It is a de Polignac number, because none of the positive numbers 2^k-221401901 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221401903) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15814415 + ... + 15814428.

It is an arithmetic number, because the mean of its divisors is an integer number (63257688).

Almost surely, 2^221401901 is an apocalyptic number.

It is an amenable number.

221401901 is a deficient number, since it is larger than the sum of its proper divisors (31628851).

221401901 is an equidigital number, since it uses as much as digits as its factorization.

221401901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31628850.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 221401901 is about 14879.5800007930. The cubic root of 221401901 is about 604.9606340071.

The spelling of 221401901 in words is "two hundred twenty-one million, four hundred one thousand, nine hundred one".