261606502 has 16 divisors (see below), whose sum is σ = 405447840. Its totient is φ = 126499968.

The previous prime is 261606493. The next prime is 261606517. The reversal of 261606502 is 205606162.

It is a super-3 number, since 3×261606502³ (a number of 26 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1774 + ... + 22942.

It is an arithmetic number, because the mean of its divisors is an integer number (25340490).

Almost surely, 2^261606502 is an apocalyptic number.

261606502 is a deficient number, since it is larger than the sum of its proper divisors (143841338).

261606502 is a wasteful number, since it uses less digits than its factorization.

261606502 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21375.

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

The square root of 261606502 is about 16174.2542950208. The cubic root of 261606502 is about 639.5622837080.

It can be divided in two parts, 26 and 1606502, that added together give a triangular number (1606528 = T₁₇₉₂).

The spelling of 261606502 in words is "two hundred sixty-one million, six hundred six thousand, five hundred two".