261663501 has 8 divisors (see below), whose sum is σ = 380601504. Its totient is φ = 158583920.

The previous prime is 261663499. The next prime is 261663509. The reversal of 261663501 is 105366162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261663501 - 2¹ = 261663499 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261663509) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3964566 + ... + 3964631.

It is an arithmetic number, because the mean of its divisors is an integer number (47575188).

Almost surely, 2^261663501 is an apocalyptic number.

It is an amenable number.

261663501 is a deficient number, since it is larger than the sum of its proper divisors (118938003).

261663501 is a wasteful number, since it uses less digits than its factorization.

261663501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7929211.

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 261663501 is about 16176.0162277367. The cubic root of 261663501 is about 639.6087297546.

The spelling of 261663501 in words is "two hundred sixty-one million, six hundred sixty-three thousand, five hundred one".