21001515407 has 2 divisors, whose sum is σ = 21001515408. Its totient is φ = 21001515406.

The previous prime is 21001515389. The next prime is 21001515413. The reversal of 21001515407 is 70451510012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21001515407 - 2³⁰ = 19927773583 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001515427) 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, 10500757703 + 10500757704.

It is an arithmetic number, because the mean of its divisors is an integer number (10500757704).

Almost surely, 2^21001515407 is an apocalyptic number.

21001515407 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001515407 is an equidigital number, since it uses as much as digits as its factorization.

21001515407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1400, while the sum is 26.

The spelling of 21001515407 in words is "twenty-one billion, one million, five hundred fifteen thousand, four hundred seven".