1210421855 has 4 divisors (see below), whose sum is σ = 1452506232. Its totient is φ = 968337480.

The previous prime is 1210421843. The next prime is 1210421857. The reversal of 1210421855 is 5581240121.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 1210421855 - 2¹⁸ = 1210159711 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 (1210421857) 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, 121042181 + ... + 121042190.

It is an arithmetic number, because the mean of its divisors is an integer number (363126558).

Almost surely, 2^1210421855 is an apocalyptic number.

1210421855 is a deficient number, since it is larger than the sum of its proper divisors (242084377).

1210421855 is an equidigital number, since it uses as much as digits as its factorization.

1210421855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 242084376.

The product of its (nonzero) digits is 3200, while the sum is 29.

The square root of 1210421855 is about 34791.1174727113. The cubic root of 1210421855 is about 1065.7260597419.

Adding to 1210421855 its reverse (5581240121), we get a palindrome (6791661976).

The spelling of 1210421855 in words is "one billion, two hundred ten million, four hundred twenty-one thousand, eight hundred fifty-five".