261553731 has 8 divisors (see below), whose sum is σ = 356158464. Its totient is φ = 170659080.

The previous prime is 261553693. The next prime is 261553739. The reversal of 261553731 is 137355162.

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

It is not a de Polignac number, because 261553731 - 2¹¹ = 261551683 is a prime.

It is a super-2 number, since 2×261553731² = 136820708400040722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 261553692 and 261553701.

It is not an unprimeable number, because it can be changed into a prime (261553739) 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, 927355 + ... + 927636.

It is an arithmetic number, because the mean of its divisors is an integer number (44519808).

Almost surely, 2^261553731 is an apocalyptic number.

261553731 is a deficient number, since it is larger than the sum of its proper divisors (94604733).

261553731 is a wasteful number, since it uses less digits than its factorization.

261553731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1855041.

The product of its digits is 18900, while the sum is 33.

The square root of 261553731 is about 16172.6228856052. The cubic root of 261553731 is about 639.5192768630.

The spelling of 261553731 in words is "two hundred sixty-one million, five hundred fifty-three thousand, seven hundred thirty-one".