21290461 has 8 divisors (see below), whose sum is σ = 21938400. Its totient is φ = 20649552.

The previous prime is 21290449. The next prime is 21290501. The reversal of 21290461 is 16409212.

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 21290461 - 2⁹ = 21289949 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21290411) 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, 4746 + ... + 8068.

It is an arithmetic number, because the mean of its divisors is an integer number (2742300).

Almost surely, 2^21290461 is an apocalyptic number.

It is an amenable number.

21290461 is a deficient number, since it is larger than the sum of its proper divisors (647939).

21290461 is a wasteful number, since it uses less digits than its factorization.

21290461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3515.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21290461 is about 4614.1587532290. The cubic root of 21290461 is about 277.1585975477.

Adding to 21290461 its reverse (16409212), we get a palindrome (37699673).

The spelling of 21290461 in words is "twenty-one million, two hundred ninety thousand, four hundred sixty-one".