21077928 has 32 divisors (see below), whose sum is σ = 58550400. Its totient is φ = 7025904.

The previous prime is 21077899. The next prime is 21077929. The reversal of 21077928 is 82977012.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21077892 and 21077901.

It is not an unprimeable number, because it can be changed into a prime (21077929) 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, 48576 + ... + 49007.

It is an arithmetic number, because the mean of its divisors is an integer number (1829700).

Almost surely, 2^21077928 is an apocalyptic number.

It is an amenable number.

21077928 is an abundant number, since it is smaller than the sum of its proper divisors (37472472).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21077928 is a wasteful number, since it uses less digits than its factorization.

21077928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97598 (or 97588 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 21077928 is about 4591.0704634105. The cubic root of 21077928 is about 276.2332621596.

The spelling of 21077928 in words is "twenty-one million, seventy-seven thousand, nine hundred twenty-eight".