21863541 has 8 divisors (see below), whose sum is σ = 33315904. Its totient is φ = 12493440.

The previous prime is 21863531. The next prime is 21863551. The reversal of 21863541 is 14536812.

It is an interprime number because it is at equal distance from previous prime (21863531) and next prime (21863551).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21863541 - 2¹⁰ = 21862517 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21863499 and 21863508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21863521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 520540 + ... + 520581.

It is an arithmetic number, because the mean of its divisors is an integer number (4164488).

Almost surely, 2^21863541 is an apocalyptic number.

21863541 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21863541 is a deficient number, since it is larger than the sum of its proper divisors (11452363).

21863541 is a wasteful number, since it uses less digits than its factorization.

21863541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1041131.

The product of its digits is 5760, while the sum is 30.

The square root of 21863541 is about 4675.8465543685. The cubic root of 21863541 is about 279.6233924894.

The spelling of 21863541 in words is "twenty-one million, eight hundred sixty-three thousand, five hundred forty-one".