1220447765 has 16 divisors (see below), whose sum is σ = 1555167600. Its totient is φ = 916270080.

The previous prime is 1220447749. The next prime is 1220447777. The reversal of 1220447765 is 5677440221.

It can be written as a sum of positive squares in 8 ways, for example, as 65399569 + 1155048196 = 8087^2 + 33986^2 .

It is not a de Polignac number, because 1220447765 - 2⁴ = 1220447749 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9095 + ... + 50235.

It is an arithmetic number, because the mean of its divisors is an integer number (97197975).

Almost surely, 2^1220447765 is an apocalyptic number.

It is an amenable number.

1220447765 is a deficient number, since it is larger than the sum of its proper divisors (334719835).

1220447765 is a wasteful number, since it uses less digits than its factorization.

1220447765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41512.

The product of its (nonzero) digits is 94080, while the sum is 38.

The square root of 1220447765 is about 34934.9075424567. The cubic root of 1220447765 is about 1068.6604382617.

Adding to 1220447765 its reverse (5677440221), we get a palindrome (6897887986).

The spelling of 1220447765 in words is "one billion, two hundred twenty million, four hundred forty-seven thousand, seven hundred sixty-five".