21179671 has 4 divisors (see below), whose sum is σ = 22425552. Its totient is φ = 19933792.

The previous prime is 21179633. The next prime is 21179677. The reversal of 21179671 is 17697112.

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

It is not a de Polignac number, because 21179671 - 2¹⁵ = 21146903 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21179677) 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, 622915 + ... + 622948.

It is an arithmetic number, because the mean of its divisors is an integer number (5606388).

Almost surely, 2^21179671 is an apocalyptic number.

21179671 is a deficient number, since it is larger than the sum of its proper divisors (1245881).

21179671 is a wasteful number, since it uses less digits than its factorization.

21179671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1245880.

The product of its digits is 5292, while the sum is 34.

The square root of 21179671 is about 4602.1376554814. The cubic root of 21179671 is about 276.6770075650.

The spelling of 21179671 in words is "twenty-one million, one hundred seventy-nine thousand, six hundred seventy-one".