261501634 has 4 divisors (see below), whose sum is σ = 392252454. Its totient is φ = 130750816.

The previous prime is 261501631. The next prime is 261501707. The reversal of 261501634 is 436105162.

261501634 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 256096009 + 5405625 = 16003^2 + 2325^2 .

It is not an unprimeable number, because it can be changed into a prime (261501631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65375407 + ... + 65375410.

Almost surely, 2^261501634 is an apocalyptic number.

261501634 is a deficient number, since it is larger than the sum of its proper divisors (130750820).

261501634 is a wasteful number, since it uses less digits than its factorization.

261501634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130750819.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 261501634 is about 16171.0121513775. The cubic root of 261501634 is about 639.4768136338.

Adding to 261501634 its reverse (436105162), we get a palindrome (697606796).

The spelling of 261501634 in words is "two hundred sixty-one million, five hundred one thousand, six hundred thirty-four".