1221351761 has 8 divisors (see below), whose sum is σ = 1406822400. Its totient is φ = 1038629088.

The previous prime is 1221351751. The next prime is 1221351797. The reversal of 1221351761 is 1671531221.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1221351761 - 2⁶ = 1221351697 is a prime.

It is a super-2 number, since 2×1221351761² = 2983400248195602242, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221351731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 686036 + ... + 687813.

It is an arithmetic number, because the mean of its divisors is an integer number (175852800).

Almost surely, 2^1221351761 is an apocalyptic number.

It is an amenable number.

1221351761 is a deficient number, since it is larger than the sum of its proper divisors (185470639).

1221351761 is a wasteful number, since it uses less digits than its factorization.

1221351761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1373983.

The product of its digits is 2520, while the sum is 29.

The square root of 1221351761 is about 34947.8434384727. The cubic root of 1221351761 is about 1068.9242284222.

Adding to 1221351761 its reverse (1671531221), we get a palindrome (2892882982).

The spelling of 1221351761 in words is "one billion, two hundred twenty-one million, three hundred fifty-one thousand, seven hundred sixty-one".