21085157407 has 2 divisors, whose sum is σ = 21085157408. Its totient is φ = 21085157406.

The previous prime is 21085157311. The next prime is 21085157461. The reversal of 21085157407 is 70475158012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21085157407 - 2³¹ = 18937673759 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21085157407.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21085157497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10542578703 + 10542578704.

It is an arithmetic number, because the mean of its divisors is an integer number (10542578704).

Almost surely, 2^21085157407 is an apocalyptic number.

21085157407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21085157407 is an equidigital number, since it uses as much as digits as its factorization.

21085157407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 78400, while the sum is 40.

It can be divided in two parts, 2108 and 5157407, that added together give a palindrome (5159515).

The spelling of 21085157407 in words is "twenty-one billion, eighty-five million, one hundred fifty-seven thousand, four hundred seven".