21136451 has 16 divisors (see below), whose sum is σ = 25098240. Its totient is φ = 17418240.

The previous prime is 21136441. The next prime is 21136463. The reversal of 21136451 is 15463112.

It is not a de Polignac number, because 21136451 - 2¹⁴ = 21120067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21136441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55580 + ... + 55958.

It is an arithmetic number, because the mean of its divisors is an integer number (1568640).

Almost surely, 2^21136451 is an apocalyptic number.

21136451 is a deficient number, since it is larger than the sum of its proper divisors (3961789).

21136451 is a wasteful number, since it uses less digits than its factorization.

21136451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 674.

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

The square root of 21136451 is about 4597.4396135240. The cubic root of 21136451 is about 276.4886803799.

Adding to 21136451 its reverse (15463112), we get a palindrome (36599563).

The spelling of 21136451 in words is "twenty-one million, one hundred thirty-six thousand, four hundred fifty-one".