21938777 has 8 divisors (see below), whose sum is σ = 25214400. Its totient is φ = 18698544.

The previous prime is 21938773. The next prime is 21938779. The reversal of 21938777 is 77783912.

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

It is a cyclic number.

It is not a de Polignac number, because 21938777 - 2² = 21938773 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21938771) 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, 7502 + ... + 10007.

It is an arithmetic number, because the mean of its divisors is an integer number (3151800).

Almost surely, 2^21938777 is an apocalyptic number.

It is an amenable number.

21938777 is a deficient number, since it is larger than the sum of its proper divisors (3275623).

21938777 is a wasteful number, since it uses less digits than its factorization.

21938777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17695.

The product of its digits is 148176, while the sum is 44.

The square root of 21938777 is about 4683.8848192499. The cubic root of 21938777 is about 279.9437684699.

The spelling of 21938777 in words is "twenty-one million, nine hundred thirty-eight thousand, seven hundred seventy-seven".