1263630821 has 2 divisors, whose sum is σ = 1263630822. Its totient is φ = 1263630820.

The previous prime is 1263630763. The next prime is 1263630827. The reversal of 1263630821 is 1280363621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1109622721 + 154008100 = 33311^2 + 12410^2 .

It is a cyclic number.

It is not a de Polignac number, because 1263630821 - 2²⁶ = 1196521957 is a prime.

It is a super-2 number, since 2×1263630821² = 3193525703562268082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1263630827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 631815410 + 631815411.

It is an arithmetic number, because the mean of its divisors is an integer number (631815411).

Almost surely, 2^1263630821 is an apocalyptic number.

It is an amenable number.

1263630821 is a deficient number, since it is larger than the sum of its proper divisors (1).

1263630821 is an equidigital number, since it uses as much as digits as its factorization.

1263630821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 1263630821 is about 35547.5853047714. The cubic root of 1263630821 is about 1081.1187598135.

The spelling of 1263630821 in words is "one billion, two hundred sixty-three million, six hundred thirty thousand, eight hundred twenty-one".