21506070715245 has 24 divisors (see below), whose sum is σ = 37304339521176. Its totient is φ = 11461550448768.

The previous prime is 21506070715231. The next prime is 21506070715271. The reversal of 21506070715245 is 54251707060512.

21506070715245 is a `hidden beast` number, since 2 + 1 + 5 + 0 + 607 + 0 + 7 + 15 + 24 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 12097729156041 + 9408341559204 = 3478179^2 + 3067302^2 .

It is not a de Polignac number, because 21506070715245 - 2⁴ = 21506070715229 is a prime.

It is a super-2 number, since 2×21506070715245² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21506070715245.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 173977794 + ... + 174101363.

It is an arithmetic number, because the mean of its divisors is an integer number (1554347480049).

Almost surely, 2^{21506070715245} is an apocalyptic number.

It is an amenable number.

21506070715245 is a deficient number, since it is larger than the sum of its proper divisors (15798268805931).

21506070715245 is a wasteful number, since it uses less digits than its factorization.

21506070715245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348080541 (or 348080538 counting only the distinct ones).

The product of its (nonzero) digits is 588000, while the sum is 45.

Adding to 21506070715245 its reverse (54251707060512), we get a palindrome (75757777775757).

The spelling of 21506070715245 in words is "twenty-one trillion, five hundred six billion, seventy million, seven hundred fifteen thousand, two hundred forty-five".