21988075231 has 2 divisors, whose sum is σ = 21988075232. Its totient is φ = 21988075230.

The previous prime is 21988075171. The next prime is 21988075237. The reversal of 21988075231 is 13257088912.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21988075231 - 2¹⁹ = 21987550943 is a prime.

It is a super-2 number, since 2×21988075231² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21988075237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10994037615 + 10994037616.

It is an arithmetic number, because the mean of its divisors is an integer number (10994037616).

Almost surely, 2^21988075231 is an apocalyptic number.

21988075231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21988075231 is an equidigital number, since it uses as much as digits as its factorization.

21988075231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 241920, while the sum is 46.

The spelling of 21988075231 in words is "twenty-one billion, nine hundred eighty-eight million, seventy-five thousand, two hundred thirty-one".