21738521541 has 16 divisors (see below), whose sum is σ = 31624976448. Its totient is φ = 13172649600.

The previous prime is 21738521447. The next prime is 21738521557. The reversal of 21738521541 is 14512583712.

It is not a de Polignac number, because 21738521541 - 2¹¹ = 21738519493 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21738521541.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21738521641) 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 in 15 ways as a sum of consecutive naturals, for example, 156321 + ... + 260601.

It is an arithmetic number, because the mean of its divisors is an integer number (1976561028).

Almost surely, 2^21738521541 is an apocalyptic number.

It is an amenable number.

21738521541 is a deficient number, since it is larger than the sum of its proper divisors (9886454907).

21738521541 is a wasteful number, since it uses less digits than its factorization.

21738521541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110612.

The product of its digits is 67200, while the sum is 39.

The spelling of 21738521541 in words is "twenty-one billion, seven hundred thirty-eight million, five hundred twenty-one thousand, five hundred forty-one".