21395380 has 24 divisors (see below), whose sum is σ = 45212832. Its totient is φ = 8504352.

The previous prime is 21395329. The next prime is 21395383. The reversal of 21395380 is 8359312.

It is a happy number.

It is a zygodrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21395383) 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, 22 + ... + 6541.

It is an arithmetic number, because the mean of its divisors is an integer number (1883868).

Almost surely, 2^21395380 is an apocalyptic number.

21395380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21395380 is an abundant number, since it is smaller than the sum of its proper divisors (23817452).

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

21395380 is a wasteful number, since it uses less digits than its factorization.

21395380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6735 (or 6733 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 21395380 is about 4625.5140254895. The cubic root of 21395380 is about 277.6131292115.

The spelling of 21395380 in words is "twenty-one million, three hundred ninety-five thousand, three hundred eighty".