21045244100542 has 16 divisors (see below), whose sum is σ = 33425170138800. Its totient is φ = 9903534450048.

The previous prime is 21045244100411. The next prime is 21045244100581. The reversal of 21045244100542 is 24500144254012.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 21045244100498 and 21045244100507.

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, 279417 + ... + 6493732.

It is an arithmetic number, because the mean of its divisors is an integer number (2089073133675).

Almost surely, 2^{21045244100542} is an apocalyptic number.

21045244100542 is a deficient number, since it is larger than the sum of its proper divisors (12379926038258).

21045244100542 is a wasteful number, since it uses less digits than its factorization.

21045244100542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6864555.

The product of its (nonzero) digits is 51200, while the sum is 34.

Adding to 21045244100542 its reverse (24500144254012), we get a palindrome (45545388354554).

The spelling of 21045244100542 in words is "twenty-one trillion, forty-five billion, two hundred forty-four million, one hundred thousand, five hundred forty-two".