21210501541 has 4 divisors (see below), whose sum is σ = 21211437952. Its totient is φ = 21209565132.

The previous prime is 21210501509. The next prime is 21210501547. The reversal of 21210501541 is 14510501212.

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 not a de Polignac number, because 21210501541 - 2⁵ = 21210501509 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 (21210501547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 433365 + ... + 479818.

It is an arithmetic number, because the mean of its divisors is an integer number (5302859488).

Almost surely, 2^21210501541 is an apocalyptic number.

It is an amenable number.

21210501541 is a deficient number, since it is larger than the sum of its proper divisors (936411).

21210501541 is an equidigital number, since it uses as much as digits as its factorization.

21210501541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 936410.

The product of its (nonzero) digits is 400, while the sum is 22.

The spelling of 21210501541 in words is "twenty-one billion, two hundred ten million, five hundred one thousand, five hundred forty-one".