261639142 has 4 divisors (see below), whose sum is σ = 392458716. Its totient is φ = 130819570.

The previous prime is 261639113. The next prime is 261639149. The reversal of 261639142 is 241936162.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 261639098 and 261639107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261639149) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65409784 + ... + 65409787.

It is an arithmetic number, because the mean of its divisors is an integer number (98114679).

Almost surely, 2^261639142 is an apocalyptic number.

261639142 is a deficient number, since it is larger than the sum of its proper divisors (130819574).

261639142 is a wasteful number, since it uses less digits than its factorization.

261639142 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130819573.

The product of its digits is 15552, while the sum is 34.

The square root of 261639142 is about 16175.2632745189. The cubic root of 261639142 is about 639.5888814730.

The spelling of 261639142 in words is "two hundred sixty-one million, six hundred thirty-nine thousand, one hundred forty-two".