21506071220507 has 4 divisors (see below), whose sum is σ = 22771134233496. Its totient is φ = 20241008207520.

The previous prime is 21506071220497. The next prime is 21506071220531. The reversal of 21506071220507 is 70502217060512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21506071220507 - 2¹² = 21506071216411 is a prime.

It is a super-2 number, since 2×21506071220507² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21506071220597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 632531506469 + ... + 632531506502.

It is an arithmetic number, because the mean of its divisors is an integer number (5692783558374).

Almost surely, 2^{21506071220507} is an apocalyptic number.

21506071220507 is a deficient number, since it is larger than the sum of its proper divisors (1265063012989).

21506071220507 is a wasteful number, since it uses less digits than its factorization.

21506071220507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1265063012988.

The product of its (nonzero) digits is 58800, while the sum is 38.

The spelling of 21506071220507 in words is "twenty-one trillion, five hundred six billion, seventy-one million, two hundred twenty thousand, five hundred seven".