261651345 has 32 divisors (see below), whose sum is σ = 434324352. Its totient is φ = 134410752.

The previous prime is 261651343. The next prime is 261651359. The reversal of 261651345 is 543156162.

It is not a de Polignac number, because 261651345 - 2¹ = 261651343 is a prime.

It is a super-2 number, since 2×261651345² = 136922852680618050, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261651343) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 44307 + ... + 49863.

It is an arithmetic number, because the mean of its divisors is an integer number (13572636).

Almost surely, 2^261651345 is an apocalyptic number.

It is an amenable number.

261651345 is a deficient number, since it is larger than the sum of its proper divisors (172673007).

261651345 is a wasteful number, since it uses less digits than its factorization.

261651345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5681.

The product of its digits is 21600, while the sum is 33.

The square root of 261651345 is about 16175.6404819098. The cubic root of 261651345 is about 639.5988249162.

The spelling of 261651345 in words is "two hundred sixty-one million, six hundred fifty-one thousand, three hundred forty-five".