21413451 has 4 divisors (see below), whose sum is σ = 28551272. Its totient is φ = 14275632.

The previous prime is 21413449. The next prime is 21413459. The reversal of 21413451 is 15431412.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21413451 - 2¹ = 21413449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21413459) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3568906 + ... + 3568911.

It is an arithmetic number, because the mean of its divisors is an integer number (7137818).

Almost surely, 2^21413451 is an apocalyptic number.

21413451 is a deficient number, since it is larger than the sum of its proper divisors (7137821).

21413451 is an equidigital number, since it uses as much as digits as its factorization.

21413451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7137820.

The product of its digits is 480, while the sum is 21.

The square root of 21413451 is about 4627.4670177107. The cubic root of 21413451 is about 277.6912665649.

Adding to 21413451 its reverse (15431412), we get a palindrome (36844863).

It can be divided in two parts, 214134 and 51, that added together give a triangular number (214185 = T₆₅₄).

The spelling of 21413451 in words is "twenty-one million, four hundred thirteen thousand, four hundred fifty-one".