21351461 has 4 divisors (see below), whose sum is σ = 21366624. Its totient is φ = 21336300.

The previous prime is 21351457. The next prime is 21351469. The reversal of 21351461 is 16415312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21351461 - 2² = 21351457 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351469) 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 3 ways as a sum of consecutive naturals, for example, 5225 + ... + 8366.

It is an arithmetic number, because the mean of its divisors is an integer number (5341656).

Almost surely, 2^21351461 is an apocalyptic number.

It is an amenable number.

21351461 is a deficient number, since it is larger than the sum of its proper divisors (15163).

21351461 is a wasteful number, since it uses less digits than its factorization.

21351461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15162.

The product of its digits is 720, while the sum is 23.

The square root of 21351461 is about 4620.7641142997. The cubic root of 21351461 is about 277.4230438879.

Adding to 21351461 its reverse (16415312), we get a palindrome (37766773).

It can be divided in two parts, 21351 and 461, that added together give a palindrome (21812).

The spelling of 21351461 in words is "twenty-one million, three hundred fifty-one thousand, four hundred sixty-one".