263421989 has 2 divisors, whose sum is σ = 263421990. Its totient is φ = 263421988.

The previous prime is 263421971. The next prime is 263422001. The reversal of 263421989 is 989124362.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 257345764 + 6076225 = 16042^2 + 2465^2 .

It is a cyclic number.

It is not a de Polignac number, because 263421989 - 2¹² = 263417893 is a prime.

It is a super-2 number, since 2×263421989² = 138782288577432242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (263421089) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 131710994 + 131710995.

It is an arithmetic number, because the mean of its divisors is an integer number (131710995).

Almost surely, 2^263421989 is an apocalyptic number.

It is an amenable number.

263421989 is a deficient number, since it is larger than the sum of its proper divisors (1).

263421989 is an equidigital number, since it uses as much as digits as its factorization.

263421989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 44.

The square root of 263421989 is about 16230.2800037461. The cubic root of 263421989 is about 641.0383445755.

The spelling of 263421989 in words is "two hundred sixty-three million, four hundred twenty-one thousand, nine hundred eighty-nine".