21319877 has 4 divisors (see below), whose sum is σ = 21839916. Its totient is φ = 20799840.

The previous prime is 21319849. The next prime is 21319889. The reversal of 21319877 is 77891312.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10023556 + 11296321 = 3166^2 + 3361^2 .

It is a cyclic number.

It is not a de Polignac number, because 21319877 - 2⁶ = 21319813 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21319877.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21319817) 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, 259958 + ... + 260039.

It is an arithmetic number, because the mean of its divisors is an integer number (5459979).

Almost surely, 2^21319877 is an apocalyptic number.

It is an amenable number.

21319877 is a deficient number, since it is larger than the sum of its proper divisors (520039).

21319877 is an equidigital number, since it uses as much as digits as its factorization.

21319877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520038.

The product of its digits is 21168, while the sum is 38.

The square root of 21319877 is about 4617.3452329234. The cubic root of 21319877 is about 277.2861843476.

The spelling of 21319877 in words is "twenty-one million, three hundred nineteen thousand, eight hundred seventy-seven".