21043511407 has 2 divisors, whose sum is σ = 21043511408. Its totient is φ = 21043511406.

The previous prime is 21043511399. The next prime is 21043511443. The reversal of 21043511407 is 70411534012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21043511407 - 2³ = 21043511399 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21043511497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10521755703 + 10521755704.

It is an arithmetic number, because the mean of its divisors is an integer number (10521755704).

Almost surely, 2^21043511407 is an apocalyptic number.

21043511407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21043511407 is an equidigital number, since it uses as much as digits as its factorization.

21043511407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3360, while the sum is 28.

The spelling of 21043511407 in words is "twenty-one billion, forty-three million, five hundred eleven thousand, four hundred seven".