21555041 has 2 divisors, whose sum is σ = 21555042. Its totient is φ = 21555040.

The previous prime is 21555029. The next prime is 21555067. The reversal of 21555041 is 14055512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12222016 + 9333025 = 3496^2 + 3055^2 .

It is a cyclic number.

It is not a de Polignac number, because 21555041 - 2¹⁸ = 21292897 is a prime.

It is a Chen prime.

It is equal to p_1362830 and since 21555041 and 1362830 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21554998 and 21555016.

It is not a weakly prime, because it can be changed into another prime (21554041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10777520 + 10777521.

It is an arithmetic number, because the mean of its divisors is an integer number (10777521).

Almost surely, 2^21555041 is an apocalyptic number.

It is an amenable number.

21555041 is a deficient number, since it is larger than the sum of its proper divisors (1).

21555041 is an equidigital number, since it uses as much as digits as its factorization.

21555041 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 21555041 is about 4642.7406776601. The cubic root of 21555041 is about 278.3019724747.

The spelling of 21555041 in words is "twenty-one million, five hundred fifty-five thousand, forty-one".