1221125636 has 6 divisors (see below), whose sum is σ = 2136969870. Its totient is φ = 610562816.

The previous prime is 1221125627. The next prime is 1221125641. The reversal of 1221125636 is 6365211221.

It can be written as a sum of positive squares in only one way, i.e., 1217591236 + 3534400 = 34894^2 + 1880^2 .

It is a super-2 number, since 2×1221125636² = 2982295637792808992, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1221125599 and 1221125608.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 152640701 + ... + 152640708.

It is an arithmetic number, because the mean of its divisors is an integer number (356161645).

Almost surely, 2^1221125636 is an apocalyptic number.

It is an amenable number.

1221125636 is a deficient number, since it is larger than the sum of its proper divisors (915844234).

1221125636 is a wasteful number, since it uses less digits than its factorization.

1221125636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 305281413 (or 305281411 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

The square root of 1221125636 is about 34944.6081105512. The cubic root of 1221125636 is about 1068.8582563254.

Adding to 1221125636 its reverse (6365211221), we get a palindrome (7586336857).

The spelling of 1221125636 in words is "one billion, two hundred twenty-one million, one hundred twenty-five thousand, six hundred thirty-six".