21420760 has 32 divisors (see below), whose sum is σ = 48992400. Its totient is φ = 8426880.

The previous prime is 21420719. The next prime is 21420761. The reversal of 21420760 is 6702412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1950 + ... + 6829.

Almost surely, 2^21420760 is an apocalyptic number.

21420760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21420760 is an abundant number, since it is smaller than the sum of its proper divisors (27571640).

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

21420760 is a wasteful number, since it uses less digits than its factorization.

21420760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8851 (or 8847 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21420760 is about 4628.2566912392. The cubic root of 21420760 is about 277.7228575275.

The spelling of 21420760 in words is "twenty-one million, four hundred twenty thousand, seven hundred sixty".