1221571366 has 16 divisors (see below), whose sum is σ = 1852624368. Its totient is φ = 604044000.

The previous prime is 1221571357. The next prime is 1221571367. The reversal of 1221571366 is 6631751221.

It is a super-2 number, since 2×1221571366² = 2984473204462211912, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221571367) 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, 203281 + ... + 209203.

It is an arithmetic number, because the mean of its divisors is an integer number (115789023).

Almost surely, 2^1221571366 is an apocalyptic number.

1221571366 is a deficient number, since it is larger than the sum of its proper divisors (631053002).

1221571366 is a wasteful number, since it uses less digits than its factorization.

1221571366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7047.

The product of its digits is 15120, while the sum is 34.

The square root of 1221571366 is about 34950.9851935536. The cubic root of 1221571366 is about 1068.9882905117.

The spelling of 1221571366 in words is "one billion, two hundred twenty-one million, five hundred seventy-one thousand, three hundred sixty-six".