1221404536 has 32 divisors (see below), whose sum is σ = 2500081200. Its totient is φ = 554794240.

The previous prime is 1221404533. The next prime is 1221404567. The reversal of 1221404536 is 6354041221.

It is a super-2 number, since 2×1221404536² = 2983658081122750592, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221404533) 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, 148500 + ... + 156508.

Almost surely, 2^1221404536 is an apocalyptic number.

It is an amenable number.

1221404536 is an abundant number, since it is smaller than the sum of its proper divisors (1278676664).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1221404536 is a wasteful number, since it uses less digits than its factorization.

1221404536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9759 (or 9755 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 1221404536 is about 34948.5984840594. The cubic root of 1221404536 is about 1068.9396243863.

Adding to 1221404536 its reverse (6354041221), we get a palindrome (7575445757).

The spelling of 1221404536 in words is "one billion, two hundred twenty-one million, four hundred four thousand, five hundred thirty-six".