21133042501 has 4 divisors (see below), whose sum is σ = 21648482604. Its totient is φ = 20617602400.

The previous prime is 21133042453. The next prime is 21133042529. The reversal of 21133042501 is 10524033112.

It is a happy number.

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 6056886276 + 15076156225 = 77826^2 + 122785^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21133042501 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21133042531) 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, 257719990 + ... + 257720071.

It is an arithmetic number, because the mean of its divisors is an integer number (5412120651).

Almost surely, 2^21133042501 is an apocalyptic number.

It is an amenable number.

21133042501 is a deficient number, since it is larger than the sum of its proper divisors (515440103).

21133042501 is an equidigital number, since it uses as much as digits as its factorization.

21133042501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515440102.

The product of its (nonzero) digits is 720, while the sum is 22.

Adding to 21133042501 its reverse (10524033112), we get a palindrome (31657075613).

The spelling of 21133042501 in words is "twenty-one billion, one hundred thirty-three million, forty-two thousand, five hundred one".