42521820 has 72 divisors (see below), whose sum is σ = 130891152. Its totient is φ = 10306560.

The previous prime is 42521807. The next prime is 42521821. The reversal of 42521820 is 2812524.

It is a super-2 number, since 2×42521820² = 3616210352224800, which contains 22 as substring.

It is a zygodrome in base 9 and base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42521821) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4332 + ... + 10188.

Almost surely, 2^42521820 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 42521820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (65445576).

42521820 is an abundant number, since it is smaller than the sum of its proper divisors (88369332).

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

42521820 is a wasteful number, since it uses less digits than its factorization.

42521820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5891 (or 5878 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 24.

The square root of 42521820 is about 6520.8757080625. The cubic root of 42521820 is about 349.0363150253.

The spelling of 42521820 in words is "forty-two million, five hundred twenty-one thousand, eight hundred twenty".