263091721 has 2 divisors, whose sum is σ = 263091722. Its totient is φ = 263091720.

The previous prime is 263091691. The next prime is 263091791. The reversal of 263091721 is 127190362.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 260467321 + 2624400 = 16139^2 + 1620^2 .

It is a cyclic number.

It is not a de Polignac number, because 263091721 - 2⁷ = 263091593 is a prime.

It is a Chen prime.

It is equal to p_14355661 and since 263091721 and 14355661 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (263091791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 131545860 + 131545861.

It is an arithmetic number, because the mean of its divisors is an integer number (131545861).

Almost surely, 2^263091721 is an apocalyptic number.

It is an amenable number.

263091721 is a deficient number, since it is larger than the sum of its proper divisors (1).

263091721 is an equidigital number, since it uses as much as digits as its factorization.

263091721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 263091721 is about 16220.1023732898. The cubic root of 263091721 is about 640.7703297523.

The spelling of 263091721 in words is "two hundred sixty-three million, ninety-one thousand, seven hundred twenty-one".