1221521360 has 40 divisors (see below), whose sum is σ = 2847264936. Its totient is φ = 487365120.

The previous prime is 1221521347. The next prime is 1221521377. The reversal of 1221521360 is 631251221.

It can be written as a sum of positive squares in 4 ways, for example, as 63616576 + 1157904784 = 7976^2 + 34028^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×1221521360² = 2984228865872499200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12530 + ... + 50990.

Almost surely, 2^1221521360 is an apocalyptic number.

1221521360 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1221521360 is an abundant number, since it is smaller than the sum of its proper divisors (1625743576).

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

1221521360 is a wasteful number, since it uses less digits than its factorization.

1221521360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38871 (or 38865 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 1221521360 is about 34950.2698129786. The cubic root of 1221521360 is about 1068.9737036827.

Adding to 1221521360 its reverse (631251221), we get a palindrome (1852772581).

The spelling of 1221521360 in words is "one billion, two hundred twenty-one million, five hundred twenty-one thousand, three hundred sixty".