21506142715073 has 4 divisors (see below), whose sum is σ = 21544341903408. Its totient is φ = 21467943526740.

The previous prime is 21506142715069. The next prime is 21506142715091. The reversal of 21506142715073 is 37051724160512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21506142715073 - 2² = 21506142715069 is a prime.

It is a super-2 number, since 2×21506142715073² (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 (21506142715063) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19099593323 + ... + 19099594448.

It is an arithmetic number, because the mean of its divisors is an integer number (5386085475852).

Almost surely, 2^{21506142715073} is an apocalyptic number.

It is an amenable number.

21506142715073 is a deficient number, since it is larger than the sum of its proper divisors (38199188335).

21506142715073 is an equidigital number, since it uses as much as digits as its factorization.

21506142715073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38199188334.

The product of its (nonzero) digits is 352800, while the sum is 44.

Adding to 21506142715073 its reverse (37051724160512), we get a palindrome (58557866875585).

The spelling of 21506142715073 in words is "twenty-one trillion, five hundred six billion, one hundred forty-two million, seven hundred fifteen thousand, seventy-three".