1220387281 has 4 divisors (see below), whose sum is σ = 1220470000. Its totient is φ = 1220304564.

The previous prime is 1220387249. The next prime is 1220387303. The reversal of 1220387281 is 1827830221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1827830221 = 7 ⋅261118603.

It is a cyclic number.

It is not a de Polignac number, because 1220387281 - 2⁵ = 1220387249 is a prime.

It is a super-2 number, since 2×1220387281² = 2978690231253145922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1220187281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12531 + ... + 50968.

It is an arithmetic number, because the mean of its divisors is an integer number (305117500).

Almost surely, 2^1220387281 is an apocalyptic number.

It is an amenable number.

1220387281 is a deficient number, since it is larger than the sum of its proper divisors (82719).

1220387281 is an equidigital number, since it uses as much as digits as its factorization.

1220387281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82718.

The product of its (nonzero) digits is 10752, while the sum is 34.

The square root of 1220387281 is about 34934.0418646340. The cubic root of 1220387281 is about 1068.6427841057.

The spelling of 1220387281 in words is "one billion, two hundred twenty million, three hundred eighty-seven thousand, two hundred eighty-one".