21451332446 has 12 divisors (see below), whose sum is σ = 33248452176. Its totient is φ = 10379676060.

The previous prime is 21451332439. The next prime is 21451332449. The reversal of 21451332446 is 64423315412.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21451332449) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5578550 + ... + 5582393.

It is an arithmetic number, because the mean of its divisors is an integer number (2770704348).

Almost surely, 2^21451332446 is an apocalyptic number.

21451332446 is a deficient number, since it is larger than the sum of its proper divisors (11797119730).

21451332446 is a wasteful number, since it uses less digits than its factorization.

21451332446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11161007 (or 11160976 counting only the distinct ones).

The product of its digits is 69120, while the sum is 35.

Adding to 21451332446 its reverse (64423315412), we get a palindrome (85874647858).

The spelling of 21451332446 in words is "twenty-one billion, four hundred fifty-one million, three hundred thirty-two thousand, four hundred forty-six".