21001253045 has 4 divisors (see below), whose sum is σ = 25201503660. Its totient is φ = 16801002432.

The previous prime is 21001253041. The next prime is 21001253047. The reversal of 21001253045 is 54035210012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5058907876 + 15942345169 = 71126^2 + 126263^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001253045 - 2² = 21001253041 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21001253045.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001253041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2100125300 + ... + 2100125309.

It is an arithmetic number, because the mean of its divisors is an integer number (6300375915).

Almost surely, 2^21001253045 is an apocalyptic number.

It is an amenable number.

21001253045 is a deficient number, since it is larger than the sum of its proper divisors (4200250615).

21001253045 is an equidigital number, since it uses as much as digits as its factorization.

21001253045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4200250614.

The product of its (nonzero) digits is 1200, while the sum is 23.

Adding to 21001253045 its reverse (54035210012), we get a palindrome (75036463057).

The spelling of 21001253045 in words is "twenty-one billion, one million, two hundred fifty-three thousand, forty-five".