1211013553 has 4 divisors (see below), whose sum is σ = 1218443248. Its totient is φ = 1203583860.

The previous prime is 1211013509. The next prime is 1211013593. The reversal of 1211013553 is 3553101121.

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, and also an emirpimes, since its reverse is a distinct semiprime: 3553101121 = 151 ⋅23530471.

It is a cyclic number.

It is not a de Polignac number, because 1211013553 - 2¹⁷ = 1210882481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1211013593) 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, 3714603 + ... + 3714928.

It is an arithmetic number, because the mean of its divisors is an integer number (304610812).

Almost surely, 2^1211013553 is an apocalyptic number.

It is an amenable number.

1211013553 is a deficient number, since it is larger than the sum of its proper divisors (7429695).

1211013553 is an equidigital number, since it uses as much as digits as its factorization.

1211013553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7429694.

The product of its (nonzero) digits is 450, while the sum is 22.

The square root of 1211013553 is about 34799.6200122932. The cubic root of 1211013553 is about 1065.8996866065.

Adding to 1211013553 its reverse (3553101121), we get a palindrome (4764114674).

The spelling of 1211013553 in words is "one billion, two hundred eleven million, thirteen thousand, five hundred fifty-three".