21790541 has 2 divisors, whose sum is σ = 21790542. Its totient is φ = 21790540.

The previous prime is 21790537. The next prime is 21790567. The reversal of 21790541 is 14509712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13293316 + 8497225 = 3646^2 + 2915^2 .

It is a cyclic number.

It is not a de Polignac number, because 21790541 - 2² = 21790537 is a prime.

It is a Chen prime.

It is equal to p_1376831 and since 21790541 and 1376831 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21790441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10895270 + 10895271.

It is an arithmetic number, because the mean of its divisors is an integer number (10895271).

Almost surely, 2^21790541 is an apocalyptic number.

It is an amenable number.

21790541 is a deficient number, since it is larger than the sum of its proper divisors (1).

21790541 is an equidigital number, since it uses as much as digits as its factorization.

21790541 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 21790541 is about 4668.0339544609. The cubic root of 21790541 is about 279.3118347189.

The spelling of 21790541 in words is "twenty-one million, seven hundred ninety thousand, five hundred forty-one".