21891454 has 8 divisors (see below), whose sum is σ = 35363160. Its totient is φ = 10103736.

The previous prime is 21891449. The next prime is 21891473. The reversal of 21891454 is 45419812.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 420964 + ... + 421015.

It is an arithmetic number, because the mean of its divisors is an integer number (4420395).

Almost surely, 2^21891454 is an apocalyptic number.

21891454 is a deficient number, since it is larger than the sum of its proper divisors (13471706).

21891454 is a wasteful number, since it uses less digits than its factorization.

21891454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 841994.

The product of its digits is 11520, while the sum is 34.

The square root of 21891454 is about 4678.8304094079. The cubic root of 21891454 is about 279.7423395000.

The spelling of 21891454 in words is "twenty-one million, eight hundred ninety-one thousand, four hundred fifty-four".