1221801513 has 12 divisors (see below), whose sum is σ = 1656227664. Its totient is φ = 801174000.

The previous prime is 1221801487. The next prime is 1221801541. The reversal of 1221801513 is 3151081221.

It is not a de Polignac number, because 1221801513 - 2⁸ = 1221801257 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1221800513) 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, 43563 + ... + 65888.

It is an arithmetic number, because the mean of its divisors is an integer number (138018972).

Almost surely, 2^1221801513 is an apocalyptic number.

It is an amenable number.

1221801513 is a deficient number, since it is larger than the sum of its proper divisors (434426151).

1221801513 is an equidigital number, since it uses as much as digits as its factorization.

1221801513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109576 (or 109515 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 24.

The square root of 1221801513 is about 34954.2774635666. The cubic root of 1221801513 is about 1069.0554196226.

Adding to 1221801513 its reverse (3151081221), we get a palindrome (4372882734).

The spelling of 1221801513 in words is "one billion, two hundred twenty-one million, eight hundred one thousand, five hundred thirteen".