1212072661 has 8 divisors (see below), whose sum is σ = 1256136120. Its totient is φ = 1168160448.

The previous prime is 1212072611. The next prime is 1212072671. The reversal of 1212072661 is 1662702121.

It can be written as a sum of positive squares in 4 ways, for example, as 17056900 + 1195015761 = 4130^2 + 34569^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1212072661 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 (1212072601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21366 + ... + 53671.

It is an arithmetic number, because the mean of its divisors is an integer number (157017015).

Almost surely, 2^1212072661 is an apocalyptic number.

It is an amenable number.

1212072661 is a deficient number, since it is larger than the sum of its proper divisors (44063459).

1212072661 is an equidigital number, since it uses as much as digits as its factorization.

1212072661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 75623.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 1212072661 is about 34814.8339217639. The cubic root of 1212072661 is about 1066.2103283119.

Adding to 1212072661 its reverse (1662702121), we get a palindrome (2874774782).

The spelling of 1212072661 in words is "one billion, two hundred twelve million, seventy-two thousand, six hundred sixty-one".