1221021544 has 16 divisors (see below), whose sum is σ = 2302651620. Its totient is φ = 606981120.

The previous prime is 1221021523. The next prime is 1221021587. The reversal of 1221021544 is 4451201221.

It can be written as a sum of positive squares in 2 ways, for example, as 1071252900 + 149768644 = 32730^2 + 12238^2 .

It is a super-2 number, since 2×1221021544² = 2981787221824287872, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 439737 + ... + 442504.

Almost surely, 2^1221021544 is an apocalyptic number.

It is an amenable number.

1221021544 is a deficient number, since it is larger than the sum of its proper divisors (1081630076).

1221021544 is a wasteful number, since it uses less digits than its factorization.

1221021544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 882420 (or 882416 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 22.

The square root of 1221021544 is about 34943.1186930989. The cubic root of 1221021544 is about 1068.8278846880.

Adding to 1221021544 its reverse (4451201221), we get a palindrome (5672222765).

The spelling of 1221021544 in words is "one billion, two hundred twenty-one million, twenty-one thousand, five hundred forty-four".