1263621 has 4 divisors (see below), whose sum is σ = 1684832. Its totient is φ = 842412.

The previous prime is 1263607. The next prime is 1263629.

It is a happy number.

1263621 is nontrivially palindromic in base 10.

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 not a de Polignac number, because 1263621 - 2⁹ = 1263109 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1263629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 210601 + ... + 210606.

It is an arithmetic number, because the mean of its divisors is an integer number (421208).

2^1263621 is an apocalyptic number.

It is an amenable number.

1263621 is a deficient number, since it is larger than the sum of its proper divisors (421211).

1263621 is an equidigital number, since it uses as much as digits as its factorization.

1263621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 421210.

The product of its digits is 432, while the sum is 21.

The square root of 1263621 is about 1124.1089804819. The cubic root of 1263621 is about 108.1115958970. Note that the first 3 decimals are identical.

It can be divided in two parts, 12636 and 21, that multiplied together give a triangular number (265356 = T₇₂₈).

The spelling of 1263621 in words is "one million, two hundred sixty-three thousand, six hundred twenty-one".