21023741 has 2 divisors, whose sum is σ = 21023742. Its totient is φ = 21023740.

The previous prime is 21023731. The next prime is 21023759. The reversal of 21023741 is 14732012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12924025 + 8099716 = 3595^2 + 2846^2 .

It is a cyclic number.

It is not a de Polignac number, because 21023741 - 2⁶ = 21023677 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21023701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511870 + 10511871.

It is an arithmetic number, because the mean of its divisors is an integer number (10511871).

Almost surely, 2^21023741 is an apocalyptic number.

It is an amenable number.

21023741 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023741 is an equidigital number, since it uses as much as digits as its factorization.

21023741 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 21023741 is about 4585.1653187208. The cubic root of 21023741 is about 275.9963461324.

Adding to 21023741 its reverse (14732012), we get a palindrome (35755753).

The spelling of 21023741 in words is "twenty-one million, twenty-three thousand, seven hundred forty-one".