1212155513 has 4 divisors (see below), whose sum is σ = 1213008768. Its totient is φ = 1211302260.

The previous prime is 1212155507. The next prime is 1212155519. The reversal of 1212155513 is 3155512121.

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 an interprime number because it is at equal distance from previous prime (1212155507) and next prime (1212155519).

It is a cyclic number.

It is not a de Polignac number, because 1212155513 - 2²⁰ = 1211106937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1212155519) 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, 424493 + ... + 427338.

It is an arithmetic number, because the mean of its divisors is an integer number (303252192).

Almost surely, 2^1212155513 is an apocalyptic number.

It is an amenable number.

1212155513 is a deficient number, since it is larger than the sum of its proper divisors (853255).

1212155513 is an equidigital number, since it uses as much as digits as its factorization.

1212155513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 853254.

The product of its digits is 1500, while the sum is 26.

The square root of 1212155513 is about 34816.0237965222. The cubic root of 1212155513 is about 1066.2346215874.

Adding to 1212155513 its reverse (3155512121), we get a palindrome (4367667634).

The spelling of 1212155513 in words is "one billion, two hundred twelve million, one hundred fifty-five thousand, five hundred thirteen".