1220671997 has 4 divisors (see below), whose sum is σ = 1221836700. Its totient is φ = 1219507296.

The previous prime is 1220671987. The next prime is 1220671999. The reversal of 1220671997 is 7991760221.

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

It can be written as a sum of positive squares in 2 ways, for example, as 455651716 + 765020281 = 21346^2 + 27659^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220671997 - 2⁴ = 1220671981 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 (1220671999) 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, 580778 + ... + 582875.

It is an arithmetic number, because the mean of its divisors is an integer number (305459175).

Almost surely, 2^1220671997 is an apocalyptic number.

It is an amenable number.

1220671997 is a deficient number, since it is larger than the sum of its proper divisors (1164703).

1220671997 is a wasteful number, since it uses less digits than its factorization.

1220671997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1164702.

The product of its (nonzero) digits is 95256, while the sum is 44.

The square root of 1220671997 is about 34938.1166779207. The cubic root of 1220671997 is about 1068.7258823280.

The spelling of 1220671997 in words is "one billion, two hundred twenty million, six hundred seventy-one thousand, nine hundred ninety-seven".