21408877 has 8 divisors (see below), whose sum is σ = 25755200. Its totient is φ = 17384544.

The previous prime is 21408851. The next prime is 21408901. The reversal of 21408877 is 77880412.

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

It is a de Polignac number, because none of the positive numbers 2^k-21408877 is a prime.

It is a super-2 number, since 2×21408877² = 916680028802258, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 80352 + ... + 80617.

It is an arithmetic number, because the mean of its divisors is an integer number (3219400).

Almost surely, 2^21408877 is an apocalyptic number.

It is an amenable number.

21408877 is a deficient number, since it is larger than the sum of its proper divisors (4346323).

21408877 is a wasteful number, since it uses less digits than its factorization.

21408877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160995.

The product of its (nonzero) digits is 25088, while the sum is 37.

The square root of 21408877 is about 4626.9727684524. The cubic root of 21408877 is about 277.6714931633.

The spelling of 21408877 in words is "twenty-one million, four hundred eight thousand, eight hundred seventy-seven".