21451154 has 4 divisors (see below), whose sum is σ = 32176734. Its totient is φ = 10725576.

The previous prime is 21451151. The next prime is 21451201. The reversal of 21451154 is 45115412.

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

It can be written as a sum of positive squares in only one way, i.e., 21409129 + 42025 = 4627^2 + 205^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21451151) 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 as a sum of consecutive naturals, namely, 5362787 + ... + 5362790.

Almost surely, 2^21451154 is an apocalyptic number.

21451154 is a deficient number, since it is larger than the sum of its proper divisors (10725580).

21451154 is a wasteful number, since it uses less digits than its factorization.

21451154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10725579.

The product of its digits is 800, while the sum is 23.

The square root of 21451154 is about 4631.5390530578. The cubic root of 21451154 is about 277.8541494658.

Adding to 21451154 its reverse (45115412), we get a palindrome (66566566).

The spelling of 21451154 in words is "twenty-one million, four hundred fifty-one thousand, one hundred fifty-four".