1213552421 has 4 divisors (see below), whose sum is σ = 1221589344. Its totient is φ = 1205515500.

The previous prime is 1213552411. The next prime is 1213552423. The reversal of 1213552421 is 1242553121.

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-1213552421 is a prime.

It is a super-2 number, since 2×1213552421² = 2945418957029922482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213552423) 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, 4018235 + ... + 4018536.

It is an arithmetic number, because the mean of its divisors is an integer number (305397336).

Almost surely, 2^1213552421 is an apocalyptic number.

It is an amenable number.

1213552421 is a deficient number, since it is larger than the sum of its proper divisors (8036923).

1213552421 is an equidigital number, since it uses as much as digits as its factorization.

1213552421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8036922.

The product of its digits is 2400, while the sum is 26.

The square root of 1213552421 is about 34836.0793000590. The cubic root of 1213552421 is about 1066.6440464713.

The spelling of 1213552421 in words is "one billion, two hundred thirteen million, five hundred fifty-two thousand, four hundred twenty-one".