21542010 has 64 divisors (see below), whose sum is σ = 62208000. Its totient is φ = 4663872.

The previous prime is 21541979. The next prime is 21542063. The reversal of 21542010 is 1024512.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1291 + ... + 6689.

It is an arithmetic number, because the mean of its divisors is an integer number (972000).

Almost surely, 2^21542010 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21542010, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31104000).

21542010 is an abundant number, since it is smaller than the sum of its proper divisors (40665990).

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

21542010 is a wasteful number, since it uses less digits than its factorization.

21542010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5435.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21542010 is about 4641.3370918303. The cubic root of 21542010 is about 278.2458791142.

Adding to 21542010 its reverse (1024512), we get a palindrome (22566522).

The spelling of 21542010 in words is "twenty-one million, five hundred forty-two thousand, ten".