21542760 has 160 divisors (see below), whose sum is σ = 74269800. Its totient is φ = 5598720.

The previous prime is 21542687. The next prime is 21542761. The reversal of 21542760 is 6724512.

It can be written as a sum of positive squares in 4 ways, for example, as 13351716 + 8191044 = 3654^2 + 2862^2 .

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21542761) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 197586 + ... + 197694.

Almost surely, 2^21542760 is an apocalyptic number.

21542760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21542760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37134900).

21542760 is an abundant number, since it is smaller than the sum of its proper divisors (52727040).

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

21542760 is a wasteful number, since it uses less digits than its factorization.

21542760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193 (or 180 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 21542760 is about 4641.4178868100. The cubic root of 21542760 is about 278.2491081844.

The spelling of 21542760 in words is "twenty-one million, five hundred forty-two thousand, seven hundred sixty".