21615544036445 has 16 divisors (see below), whose sum is σ = 26905464708672. Its totient is φ = 16658911785600.

The previous prime is 21615544036441. The next prime is 21615544036459. The reversal of 21615544036445 is 54463044551612.

It is a happy number.

It is not a de Polignac number, because 21615544036445 - 2² = 21615544036441 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21615544036393 and 21615544036402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21615544036441) 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 15 ways as a sum of consecutive naturals, for example, 688596731 + ... + 688628120.

It is an arithmetic number, because the mean of its divisors is an integer number (1681591544292).

Almost surely, 2^{21615544036445} is an apocalyptic number.

It is an amenable number.

21615544036445 is a deficient number, since it is larger than the sum of its proper divisors (5289920672227).

21615544036445 is a wasteful number, since it uses less digits than its factorization.

21615544036445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1377224972.

The product of its (nonzero) digits is 6912000, while the sum is 50.

The spelling of 21615544036445 in words is "twenty-one trillion, six hundred fifteen billion, five hundred forty-four million, thirty-six thousand, four hundred forty-five".