21702080 has 28 divisors (see below), whose sum is σ = 51678840. Its totient is φ = 8680704.

The previous prime is 21702067. The next prime is 21702089. The reversal of 21702080 is 8020712.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21702089) 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, 33590 + ... + 34229.

Almost surely, 2^21702080 is an apocalyptic number.

21702080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21702080 is an abundant number, since it is smaller than the sum of its proper divisors (29976760).

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

21702080 is an equidigital number, since it uses as much as digits as its factorization.

21702080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67836 (or 67826 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 21702080 is about 4658.5491303624. The cubic root of 21702080 is about 278.9333568125.

Adding to 21702080 its reverse (8020712), we get a palindrome (29722792).

The spelling of 21702080 in words is "twenty-one million, seven hundred two thousand, eighty".