21877798 has 16 divisors (see below), whose sum is σ = 34062336. Its totient is φ = 10531080.

The previous prime is 21877789. The next prime is 21877799. The reversal of 21877798 is 89777812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21877799) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4315 + ... + 7897.

It is an arithmetic number, because the mean of its divisors is an integer number (2128896).

Almost surely, 2^21877798 is an apocalyptic number.

21877798 is a deficient number, since it is larger than the sum of its proper divisors (12184538).

21877798 is a wasteful number, since it uses less digits than its factorization.

21877798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3699.

The product of its digits is 395136, while the sum is 49.

The square root of 21877798 is about 4677.3708426850. The cubic root of 21877798 is about 279.6841591707.

The spelling of 21877798 in words is "twenty-one million, eight hundred seventy-seven thousand, seven hundred ninety-eight".