1221845647 has 8 divisors (see below), whose sum is σ = 1340906112. Its totient is φ = 1104115800.

The previous prime is 1221845627. The next prime is 1221845689. The reversal of 1221845647 is 7465481221.

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 1221845647 - 2²³ = 1213457039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221845627) 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, 330729 + ... + 334402.

It is an arithmetic number, because the mean of its divisors is an integer number (167613264).

Almost surely, 2^1221845647 is an apocalyptic number.

1221845647 is a deficient number, since it is larger than the sum of its proper divisors (119060465).

1221845647 is a wasteful number, since it uses less digits than its factorization.

1221845647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 665309.

The product of its digits is 107520, while the sum is 40.

The square root of 1221845647 is about 34954.9087682975. The cubic root of 1221845647 is about 1069.0682916326.

The spelling of 1221845647 in words is "one billion, two hundred twenty-one million, eight hundred forty-five thousand, six hundred forty-seven".