21215045123544 has 32 divisors (see below), whose sum is σ = 54271045667520. Its totient is φ = 6907223993376.

The previous prime is 21215045123539. The next prime is 21215045123563. The reversal of 21215045123544 is 44532154051212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10278606102 + ... + 10278608165.

It is an arithmetic number, because the mean of its divisors is an integer number (1695970177110).

Almost surely, 2^{21215045123544} is an apocalyptic number.

21215045123544 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21215045123544 is an abundant number, since it is smaller than the sum of its proper divisors (33056000543976).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21215045123544 is a wasteful number, since it uses less digits than its factorization.

21215045123544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20557214319 (or 20557214315 counting only the distinct ones).

The product of its (nonzero) digits is 192000, while the sum is 39.

Adding to 21215045123544 its reverse (44532154051212), we get a palindrome (65747199174756).

The spelling of 21215045123544 in words is "twenty-one trillion, two hundred fifteen billion, forty-five million, one hundred twenty-three thousand, five hundred forty-four".