1901221 has 4 divisors (see below), whose sum is σ = 2172832. Its totient is φ = 1629612.

The previous prime is 1901219. The next prime is 1901231. The reversal of 1901221 is 1221091.

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: 1221091 = 509 ⋅2399.

It is a cyclic number.

It is not a de Polignac number, because 1901221 - 2¹ = 1901219 is a prime.

It is a super-2 number, since 2×1901221² = 7229282581682, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1901195 and 1901204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1901201) 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, 135795 + ... + 135808.

It is an arithmetic number, because the mean of its divisors is an integer number (543208).

2^1901221 is an apocalyptic number.

It is an amenable number.

1901221 is a deficient number, since it is larger than the sum of its proper divisors (271611).

1901221 is an equidigital number, since it uses as much as digits as its factorization.

1901221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271610.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 1901221 is about 1378.8477073267. The cubic root of 1901221 is about 123.8827585906.

The spelling of 1901221 in words is "one million, nine hundred one thousand, two hundred twenty-one".