261421525 has 6 divisors (see below), whose sum is σ = 324162722. Its totient is φ = 209137200.

The previous prime is 261421487. The next prime is 261421571. The reversal of 261421525 is 525124162.

It can be written as a sum of positive squares in 3 ways, for example, as 42588676 + 218832849 = 6526^2 + 14793^2 .

It is not a de Polignac number, because 261421525 - 2⁷ = 261421397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261421493 and 261421502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5228406 + ... + 5228455.

Almost surely, 2^261421525 is an apocalyptic number.

261421525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

261421525 is a deficient number, since it is larger than the sum of its proper divisors (62741197).

261421525 is a wasteful number, since it uses less digits than its factorization.

261421525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10456871 (or 10456866 counting only the distinct ones).

The product of its digits is 4800, while the sum is 28.

The square root of 261421525 is about 16168.5350294948. The cubic root of 261421525 is about 639.4115073751.

Adding to 261421525 its reverse (525124162), we get a palindrome (786545687).

The spelling of 261421525 in words is "two hundred sixty-one million, four hundred twenty-one thousand, five hundred twenty-five".