21671455 has 16 divisors (see below), whose sum is σ = 28766304. Its totient is φ = 15569280.

The previous prime is 21671431. The next prime is 21671471. The reversal of 21671455 is 55417612.

It is not a de Polignac number, because 21671455 - 2⁷ = 21671327 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2101 + ... + 6910.

It is an arithmetic number, because the mean of its divisors is an integer number (1797894).

Almost surely, 2^21671455 is an apocalyptic number.

21671455 is a deficient number, since it is larger than the sum of its proper divisors (7094849).

21671455 is a wasteful number, since it uses less digits than its factorization.

21671455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9066.

The product of its digits is 8400, while the sum is 31.

The square root of 21671455 is about 4655.2610023499. The cubic root of 21671455 is about 278.8020889741.

The spelling of 21671455 in words is "twenty-one million, six hundred seventy-one thousand, four hundred fifty-five".