1221437256 has 32 divisors (see below), whose sum is σ = 3288485760. Its totient is φ = 375826752.

The previous prime is 1221437201. The next prime is 1221437279. The reversal of 1221437256 is 6527341221.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1957120 + ... + 1957743.

It is an arithmetic number, because the mean of its divisors is an integer number (102765180).

Almost surely, 2^1221437256 is an apocalyptic number.

It is an amenable number.

1221437256 is an abundant number, since it is smaller than the sum of its proper divisors (2067048504).

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

1221437256 is a wasteful number, since it uses less digits than its factorization.

1221437256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3914885 (or 3914881 counting only the distinct ones).

The product of its digits is 20160, while the sum is 33.

The square root of 1221437256 is about 34949.0665969780. The cubic root of 1221437256 is about 1068.9491695155.

Adding to 1221437256 its reverse (6527341221), we get a palindrome (7748778477).

The spelling of 1221437256 in words is "one billion, two hundred twenty-one million, four hundred thirty-seven thousand, two hundred fifty-six".