21077420 has 96 divisors (see below), whose sum is σ = 56128128. Its totient is φ = 6469632.

The previous prime is 21077401. The next prime is 21077431. The reversal of 21077420 is 2477012.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 67184 + ... + 67496.

It is an arithmetic number, because the mean of its divisors is an integer number (584668).

Almost surely, 2^21077420 is an apocalyptic number.

21077420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21077420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28064064).

21077420 is an abundant number, since it is smaller than the sum of its proper divisors (35050708).

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

21077420 is a wasteful number, since it uses less digits than its factorization.

21077420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 379 (or 377 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 21077420 is about 4591.0151382891. The cubic root of 21077420 is about 276.2310429721.

The spelling of 21077420 in words is "twenty-one million, seventy-seven thousand, four hundred twenty".