261099601 has 4 divisors (see below), whose sum is σ = 298399552. Its totient is φ = 223799652.

The previous prime is 261099599. The next prime is 261099649. The reversal of 261099601 is 106990162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 261099601 - 2¹ = 261099599 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261099301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18649965 + ... + 18649978.

It is an arithmetic number, because the mean of its divisors is an integer number (74599888).

Almost surely, 2^261099601 is an apocalyptic number.

It is an amenable number.

261099601 is a deficient number, since it is larger than the sum of its proper divisors (37299951).

261099601 is an equidigital number, since it uses as much as digits as its factorization.

261099601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37299950.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 261099601 is about 16158.5767009350. The cubic root of 261099601 is about 639.1489346819.

The spelling of 261099601 in words is "two hundred sixty-one million, ninety-nine thousand, six hundred one".