1221945 has 8 divisors (see below), whose sum is σ = 1955136. Its totient is φ = 651696.

The previous prime is 1221937. The next prime is 1221959. The reversal of 1221945 is 5491221.

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

It is not a de Polignac number, because 1221945 - 2³ = 1221937 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40717 + ... + 40746.

It is an arithmetic number, because the mean of its divisors is an integer number (244392).

2^1221945 is an apocalyptic number.

1221945 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1221945 is a deficient number, since it is larger than the sum of its proper divisors (733191).

1221945 is an equidigital number, since it uses as much as digits as its factorization.

1221945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81471.

The product of its digits is 720, while the sum is 24.

The square root of 1221945 is about 1105.4162112073. The cubic root of 1221945 is about 106.9097267541.

The spelling of 1221945 in words is "one million, two hundred twenty-one thousand, nine hundred forty-five".