1221742151 has 4 divisors (see below), whose sum is σ = 1396276752. Its totient is φ = 1047207552.

The previous prime is 1221742103. The next prime is 1221742177. The reversal of 1221742151 is 1512471221.

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 1221742151 - 2¹⁰ = 1221741127 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221742151.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221742051) 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, 87267290 + ... + 87267303.

It is an arithmetic number, because the mean of its divisors is an integer number (349069188).

Almost surely, 2^1221742151 is an apocalyptic number.

1221742151 is a deficient number, since it is larger than the sum of its proper divisors (174534601).

1221742151 is an equidigital number, since it uses as much as digits as its factorization.

1221742151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174534600.

The product of its digits is 1120, while the sum is 26.

The square root of 1221742151 is about 34953.4283154028. The cubic root of 1221742151 is about 1069.0381057641.

The spelling of 1221742151 in words is "one billion, two hundred twenty-one million, seven hundred forty-two thousand, one hundred fifty-one".