21010250501 has 4 divisors (see below), whose sum is σ = 21010782912. Its totient is φ = 21009718092.

The previous prime is 21010250489. The next prime is 21010250507. The reversal of 21010250501 is 10505201012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21010250501 is a prime.

It is a super-2 number, since 2×21010250501² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21010250501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010250507) 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, 201821 + ... + 287666.

It is an arithmetic number, because the mean of its divisors is an integer number (5252695728).

Almost surely, 2^21010250501 is an apocalyptic number.

It is an amenable number.

21010250501 is a deficient number, since it is larger than the sum of its proper divisors (532411).

21010250501 is an equidigital number, since it uses as much as digits as its factorization.

21010250501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 532410.

The product of its (nonzero) digits is 100, while the sum is 17.

Adding to 21010250501 its reverse (10505201012), we get a palindrome (31515451513).

The spelling of 21010250501 in words is "twenty-one billion, ten million, two hundred fifty thousand, five hundred one".