21267580 has 12 divisors (see below), whose sum is σ = 44661960. Its totient is φ = 8507024.

The previous prime is 21267577. The next prime is 21267583. The reversal of 21267580 is 8576212.

It is an interprime number because it is at equal distance from previous prime (21267577) and next prime (21267583).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21267583) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 531670 + ... + 531709.

It is an arithmetic number, because the mean of its divisors is an integer number (3721830).

Almost surely, 2^21267580 is an apocalyptic number.

21267580 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21267580 is an abundant number, since it is smaller than the sum of its proper divisors (23394380).

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

21267580 is a wasteful number, since it uses less digits than its factorization.

21267580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1063388 (or 1063386 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 21267580 is about 4611.6786531587. The cubic root of 21267580 is about 277.0592738954.

The spelling of 21267580 in words is "twenty-one million, two hundred sixty-seven thousand, five hundred eighty".