1221547 has 4 divisors (see below), whose sum is σ = 1224216. Its totient is φ = 1218880.

The previous prime is 1221541. The next prime is 1221551. The reversal of 1221547 is 7451221.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1221547 - 2¹⁹ = 697259 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 454 + ... + 1627.

It is an arithmetic number, because the mean of its divisors is an integer number (306054).

2^1221547 is an apocalyptic number.

1221547 is a deficient number, since it is larger than the sum of its proper divisors (2669).

1221547 is an equidigital number, since it uses as much as digits as its factorization.

1221547 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2668.

The product of its digits is 560, while the sum is 22.

The square root of 1221547 is about 1105.2361738561. The cubic root of 1221547 is about 106.8981182961.

Adding to 1221547 its reverse (7451221), we get a palindrome (8672768).

The spelling of 1221547 in words is "one million, two hundred twenty-one thousand, five hundred forty-seven".