21021503541 has 16 divisors (see below), whose sum is σ = 28685119680. Its totient is φ = 13689906560.

The previous prime is 21021503509. The next prime is 21021503543. The reversal of 21021503541 is 14530512012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21021503541 - 2⁵ = 21021503509 is a prime.

It is a super-2 number, since 2×21021503541² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021503543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 452130 + ... + 496451.

It is an arithmetic number, because the mean of its divisors is an integer number (1792819980).

Almost surely, 2^21021503541 is an apocalyptic number.

It is an amenable number.

21021503541 is a deficient number, since it is larger than the sum of its proper divisors (7663616139).

21021503541 is an equidigital number, since it uses as much as digits as its factorization.

21021503541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 948756.

The product of its (nonzero) digits is 1200, while the sum is 24.

The spelling of 21021503541 in words is "twenty-one billion, twenty-one million, five hundred three thousand, five hundred forty-one".