21102541 has 2 divisors, whose sum is σ = 21102542. Its totient is φ = 21102540.

The previous prime is 21102493. The next prime is 21102547. The reversal of 21102541 is 14520112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14600041 + 6502500 = 3821^2 + 2550^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102541 - 2²³ = 12713933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551270 + 10551271.

It is an arithmetic number, because the mean of its divisors is an integer number (10551271).

Almost surely, 2^21102541 is an apocalyptic number.

It is an amenable number.

21102541 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102541 is an equidigital number, since it uses as much as digits as its factorization.

21102541 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80, while the sum is 16.

The square root of 21102541 is about 4593.7502108843. The cubic root of 21102541 is about 276.3407408547.

Adding to 21102541 its reverse (14520112), we get a palindrome (35622653).

The spelling of 21102541 in words is "twenty-one million, one hundred two thousand, five hundred forty-one".