1221189772 has 24 divisors (see below), whose sum is σ = 2332248912. Its totient is φ = 554875200.

The previous prime is 1221189743. The next prime is 1221189787. The reversal of 1221189772 is 2779811221.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 216022 + ... + 221602.

It is an arithmetic number, because the mean of its divisors is an integer number (97177038).

Almost surely, 2^1221189772 is an apocalyptic number.

It is an amenable number.

1221189772 is a deficient number, since it is larger than the sum of its proper divisors (1111059140).

1221189772 is a wasteful number, since it uses less digits than its factorization.

1221189772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10569 (or 10567 counting only the distinct ones).

The product of its digits is 28224, while the sum is 40.

The square root of 1221189772 is about 34945.5257794185. The cubic root of 1221189772 is about 1068.8769688671.

The spelling of 1221189772 in words is "one billion, two hundred twenty-one million, one hundred eighty-nine thousand, seven hundred seventy-two".