21045415023545 has 16 divisors (see below), whose sum is σ = 28136539392768. Its totient is φ = 14980101987840.

The previous prime is 21045415023539. The next prime is 21045415023547. The reversal of 21045415023545 is 54532051454012.

It is a happy number.

It is not a de Polignac number, because 21045415023545 - 2¹⁰ = 21045415022521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21045415023547) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4070677304 + ... + 4070682473.

It is an arithmetic number, because the mean of its divisors is an integer number (1758533712048).

Almost surely, 2^{21045415023545} is an apocalyptic number.

It is an amenable number.

21045415023545 is a deficient number, since it is larger than the sum of its proper divisors (7091124369223).

21045415023545 is a wasteful number, since it uses less digits than its factorization.

21045415023545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8141359840.

The product of its (nonzero) digits is 480000, while the sum is 41.

Adding to 21045415023545 its reverse (54532051454012), we get a palindrome (75577466477557).

The spelling of 21045415023545 in words is "twenty-one trillion, forty-five billion, four hundred fifteen million, twenty-three thousand, five hundred forty-five".