21123741 has 24 divisors (see below), whose sum is σ = 30886272. Its totient is φ = 12796800.

The previous prime is 21123721. The next prime is 21123757. The reversal of 21123741 is 14732112.

It is not a de Polignac number, because 21123741 - 2⁵ = 21123709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48796 + ... + 49226.

It is an arithmetic number, because the mean of its divisors is an integer number (1286928).

Almost surely, 2^21123741 is an apocalyptic number.

It is an amenable number.

21123741 is a deficient number, since it is larger than the sum of its proper divisors (9762531).

21123741 is a wasteful number, since it uses less digits than its factorization.

21123741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513 (or 482 counting only the distinct ones).

The product of its digits is 336, while the sum is 21.

The square root of 21123741 is about 4596.0571145276. The cubic root of 21123741 is about 276.4332488766.

Adding to 21123741 its reverse (14732112), we get a palindrome (35855853).

The spelling of 21123741 in words is "twenty-one million, one hundred twenty-three thousand, seven hundred forty-one".