21002221545 has 32 divisors (see below), whose sum is σ = 34225693824. Its totient is φ = 10995264000.

The previous prime is 21002221529. The next prime is 21002221547. The reversal of 21002221545 is 54512220012.

It is not a de Polignac number, because 21002221545 - 2⁴ = 21002221529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21002221547) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 185595 + ... + 276495.

It is an arithmetic number, because the mean of its divisors is an integer number (1069552932).

Almost surely, 2^21002221545 is an apocalyptic number.

It is an amenable number.

21002221545 is a deficient number, since it is larger than the sum of its proper divisors (13223472279).

21002221545 is a wasteful number, since it uses less digits than its factorization.

21002221545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91193.

The product of its (nonzero) digits is 1600, while the sum is 24.

Adding to 21002221545 its reverse (54512220012), we get a palindrome (75514441557).

The spelling of 21002221545 in words is "twenty-one billion, two million, two hundred twenty-one thousand, five hundred forty-five".