21474155 has 4 divisors (see below), whose sum is σ = 25768992. Its totient is φ = 17179320.

The previous prime is 21474143. The next prime is 21474217. The reversal of 21474155 is 55147412.

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

It is not a de Polignac number, because 21474155 - 2⁴ = 21474139 is a prime.

It is a super-2 number, since 2×21474155² = 922278665928050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2147411 + ... + 2147420.

It is an arithmetic number, because the mean of its divisors is an integer number (6442248).

Almost surely, 2^21474155 is an apocalyptic number.

21474155 is a deficient number, since it is larger than the sum of its proper divisors (4294837).

21474155 is an equidigital number, since it uses as much as digits as its factorization.

21474155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4294836.

The product of its digits is 5600, while the sum is 29.

The square root of 21474155 is about 4634.0214716809. The cubic root of 21474155 is about 277.9534236964.

The spelling of 21474155 in words is "twenty-one million, four hundred seventy-four thousand, one hundred fifty-five".