21478877 has 8 divisors (see below), whose sum is σ = 25339392. Its totient is φ = 17816400.

The previous prime is 21478867. The next prime is 21478883. The reversal of 21478877 is 77887412.

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

It is not a de Polignac number, because 21478877 - 2⁴ = 21478861 is a prime.

It is a super-2 number, since 2×21478877² = 922684314362258, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21478817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49274 + ... + 49707.

It is an arithmetic number, because the mean of its divisors is an integer number (3167424).

Almost surely, 2^21478877 is an apocalyptic number.

It is an amenable number.

21478877 is a deficient number, since it is larger than the sum of its proper divisors (3860515).

21478877 is an equidigital number, since it uses as much as digits as its factorization.

21478877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99019.

The product of its digits is 175616, while the sum is 44.

The square root of 21478877 is about 4634.5309363516. The cubic root of 21478877 is about 277.9737954701.

The spelling of 21478877 in words is "twenty-one million, four hundred seventy-eight thousand, eight hundred seventy-seven".