1213096721 has 4 divisors (see below), whose sum is σ = 1213462512. Its totient is φ = 1212730932.

The previous prime is 1213096711. The next prime is 1213096723. The reversal of 1213096721 is 1276903121.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1213096721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1213096723) 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, 177875 + ... + 184568.

It is an arithmetic number, because the mean of its divisors is an integer number (303365628).

Almost surely, 2^1213096721 is an apocalyptic number.

It is an amenable number.

1213096721 is a deficient number, since it is larger than the sum of its proper divisors (365791).

1213096721 is an equidigital number, since it uses as much as digits as its factorization.

1213096721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365790.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 1213096721 is about 34829.5380532100. The cubic root of 1213096721 is about 1066.5105182343.

Adding to 1213096721 its reverse (1276903121), we get a palindrome (2489999842).

The spelling of 1213096721 in words is "one billion, two hundred thirteen million, ninety-six thousand, seven hundred twenty-one".