1263821953 has 4 divisors (see below), whose sum is σ = 1265904640. Its totient is φ = 1261739268.

The previous prime is 1263821921. The next prime is 1263821957. The reversal of 1263821953 is 3591283621.

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: 3591283621 = 2341 ⋅1534081.

It is a cyclic number.

It is not a de Polignac number, because 1263821953 - 2⁵ = 1263821921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1263821957) 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, 1040433 + ... + 1041646.

It is an arithmetic number, because the mean of its divisors is an integer number (316476160).

Almost surely, 2^1263821953 is an apocalyptic number.

It is an amenable number.

1263821953 is a deficient number, since it is larger than the sum of its proper divisors (2082687).

1263821953 is an equidigital number, since it uses as much as digits as its factorization.

1263821953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2082686.

The product of its digits is 77760, while the sum is 40.

The square root of 1263821953 is about 35550.2735995098. The cubic root of 1263821953 is about 1081.1732657051.

The spelling of 1263821953 in words is "one billion, two hundred sixty-three million, eight hundred twenty-one thousand, nine hundred fifty-three".