21310780 has 24 divisors (see below), whose sum is σ = 47108880. Its totient is φ = 8075520.

The previous prime is 21310771. The next prime is 21310801. The reversal of 21310780 is 8701312.

It is a zygodrome in base 3.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27661 + ... + 28420.

It is an arithmetic number, because the mean of its divisors is an integer number (1962870).

Almost surely, 2^21310780 is an apocalyptic number.

21310780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21310780 is an abundant number, since it is smaller than the sum of its proper divisors (25798100).

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

21310780 is a wasteful number, since it uses less digits than its factorization.

21310780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56109 (or 56107 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21310780 is about 4616.3600379520. The cubic root of 21310780 is about 277.2467402290.

The spelling of 21310780 in words is "twenty-one million, three hundred ten thousand, seven hundred eighty".