1221917153 has 8 divisors (see below), whose sum is σ = 1225637376. Its totient is φ = 1218204000.

The previous prime is 1221917149. The next prime is 1221917183. The reversal of 1221917153 is 3517191221.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 1221917153 - 2² = 1221917149 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221917183) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 625328 + ... + 627278.

It is an arithmetic number, because the mean of its divisors is an integer number (153204672).

Almost surely, 2^1221917153 is an apocalyptic number.

It is an amenable number.

1221917153 is a deficient number, since it is larger than the sum of its proper divisors (3720223).

1221917153 is an equidigital number, since it uses as much as digits as its factorization.

1221917153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3535.

The product of its digits is 3780, while the sum is 32.

The square root of 1221917153 is about 34955.9315853547. The cubic root of 1221917153 is about 1069.0891462324.

The spelling of 1221917153 in words is "one billion, two hundred twenty-one million, nine hundred seventeen thousand, one hundred fifty-three".