42021520 has 40 divisors (see below), whose sum is σ = 98067384. Its totient is φ = 16745472.

The previous prime is 42021517. The next prime is 42021547. The reversal of 42021520 is 2512024.

It can be written as a sum of positive squares in 4 ways, for example, as 82944 + 41938576 = 288^2 + 6476^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×42021520² = 3531616286220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a junction number, because it is equal to n+sod(n) for n = 42021494 and 42021503.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24532 + ... + 26188.

Almost surely, 2^42021520 is an apocalyptic number.

42021520 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

42021520 is an abundant number, since it is smaller than the sum of its proper divisors (56045864).

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

42021520 is a wasteful number, since it uses less digits than its factorization.

42021520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1987 (or 1981 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 42021520 is about 6482.4007898309. The cubic root of 42021520 is about 347.6620226799.

Adding to 42021520 its reverse (2512024), we get a palindrome (44533544).

The spelling of 42021520 in words is "forty-two million, twenty-one thousand, five hundred twenty".