21461751 has 24 divisors (see below), whose sum is σ = 32011200. Its totient is φ = 13848576.

The previous prime is 21461747. The next prime is 21461753. The reversal of 21461751 is 15716412.

It is a happy number.

It is not a de Polignac number, because 21461751 - 2² = 21461747 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21461753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 47575 + ... + 48023.

It is an arithmetic number, because the mean of its divisors is an integer number (1333800).

Almost surely, 2^21461751 is an apocalyptic number.

21461751 is a deficient number, since it is larger than the sum of its proper divisors (10549449).

21461751 is a wasteful number, since it uses less digits than its factorization.

21461751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 615 (or 612 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 21461751 is about 4632.6829159786. The cubic root of 21461751 is about 277.8998958112.

The spelling of 21461751 in words is "twenty-one million, four hundred sixty-one thousand, seven hundred fifty-one".