1220437261 has 4 divisors (see below), whose sum is σ = 1226632572. Its totient is φ = 1214241952.

The previous prime is 1220437249. The next prime is 1220437291. The reversal of 1220437261 is 1627340221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1627340221 = 13 ⋅125180017.

It can be written as a sum of positive squares in 2 ways, for example, as 649944036 + 570493225 = 25494^2 + 23885^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220437261 - 2¹⁹ = 1219912973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1220437291) 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, 3097360 + ... + 3097753.

It is an arithmetic number, because the mean of its divisors is an integer number (306658143).

Almost surely, 2^1220437261 is an apocalyptic number.

It is an amenable number.

1220437261 is a deficient number, since it is larger than the sum of its proper divisors (6195311).

1220437261 is an equidigital number, since it uses as much as digits as its factorization.

1220437261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6195310.

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 1220437261 is about 34934.7572053965. The cubic root of 1220437261 is about 1068.6573723811.

Adding to 1220437261 its reverse (1627340221), we get a palindrome (2847777482).

The spelling of 1220437261 in words is "one billion, two hundred twenty million, four hundred thirty-seven thousand, two hundred sixty-one".