21457311 has 8 divisors (see below), whose sum is σ = 28663344. Its totient is φ = 14278080.

The previous prime is 21457307. The next prime is 21457313. The reversal of 21457311 is 11375412.

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

It is not a de Polignac number, because 21457311 - 2² = 21457307 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21457313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4750 + ... + 8091.

It is an arithmetic number, because the mean of its divisors is an integer number (3582918).

Almost surely, 2^21457311 is an apocalyptic number.

21457311 is a deficient number, since it is larger than the sum of its proper divisors (7206033).

21457311 is a wasteful number, since it uses less digits than its factorization.

21457311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13401.

The product of its digits is 840, while the sum is 24.

The square root of 21457311 is about 4632.2036872314. The cubic root of 21457311 is about 277.8807305431.

The spelling of 21457311 in words is "twenty-one million, four hundred fifty-seven thousand, three hundred eleven".