25421520 has 80 divisors (see below), whose sum is σ = 79941312. Its totient is φ = 6681600.

The previous prime is 25421483. The next prime is 25421521. The reversal of 25421520 is 2512452.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×25421520² = 1292507358220800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25421521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16795 + ... + 18245.

Almost surely, 2^25421520 is an apocalyptic number.

25421520 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 25421520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39970656).

25421520 is an abundant number, since it is smaller than the sum of its proper divisors (54519792).

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

25421520 is a wasteful number, since it uses less digits than its factorization.

25421520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1540 (or 1534 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 25421520 is about 5041.9758031946. The cubic root of 25421520 is about 294.0359991089.

Adding to 25421520 its reverse (2512452), we get a palindrome (27933972).

The spelling of 25421520 in words is "twenty-five million, four hundred twenty-one thousand, five hundred twenty".