1221311201 has 12 divisors (see below), whose sum is σ = 1400802816. Its totient is φ = 1062007320.

The previous prime is 1221311159. The next prime is 1221311209. The reversal of 1221311201 is 1021131221.

It is a de Polignac number, because none of the positive numbers 2^k-1221311201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221311209) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 216641 + ... + 222206.

It is an arithmetic number, because the mean of its divisors is an integer number (116733568).

Almost surely, 2^1221311201 is an apocalyptic number.

1221311201 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221311201 is a deficient number, since it is larger than the sum of its proper divisors (179491615).

1221311201 is a wasteful number, since it uses less digits than its factorization.

1221311201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438892 (or 438881 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 1221311201 is about 34947.2631403376. The cubic root of 1221311201 is about 1068.9123956186.

Adding to 1221311201 its reverse (1021131221), we get a palindrome (2242442422).

The spelling of 1221311201 in words is "one billion, two hundred twenty-one million, three hundred eleven thousand, two hundred one".