21040143991 has 2 divisors, whose sum is σ = 21040143992. Its totient is φ = 21040143990.

The previous prime is 21040143983. The next prime is 21040144007. The reversal of 21040143991 is 19934104012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21040143991 - 2³ = 21040143983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21040143911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10520071995 + 10520071996.

It is an arithmetic number, because the mean of its divisors is an integer number (10520071996).

Almost surely, 2^21040143991 is an apocalyptic number.

21040143991 is a deficient number, since it is larger than the sum of its proper divisors (1).

21040143991 is an equidigital number, since it uses as much as digits as its factorization.

21040143991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 34.

The spelling of 21040143991 in words is "twenty-one billion, forty million, one hundred forty-three thousand, nine hundred ninety-one".