21254761 has 8 divisors (see below), whose sum is σ = 23814144. Its totient is φ = 18799920.

The previous prime is 21254729. The next prime is 21254789. The reversal of 21254761 is 16745212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21254761 - 2⁵ = 21254729 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21254161) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25705 + ... + 26518.

It is an arithmetic number, because the mean of its divisors is an integer number (2976768).

Almost surely, 2^21254761 is an apocalyptic number.

It is an amenable number.

21254761 is a deficient number, since it is larger than the sum of its proper divisors (2559383).

21254761 is a wasteful number, since it uses less digits than its factorization.

21254761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52271.

The product of its digits is 3360, while the sum is 28.

The square root of 21254761 is about 4610.2886026799. The cubic root of 21254761 is about 277.0035970287.

Adding to 21254761 its reverse (16745212), we get a palindrome (37999973).

It can be divided in two parts, 2125 and 4761, that added together give a palindrome (6886).

The spelling of 21254761 in words is "twenty-one million, two hundred fifty-four thousand, seven hundred sixty-one".