261722645 has 16 divisors (see below), whose sum is σ = 323760000. Its totient is φ = 202958784.

The previous prime is 261722627. The next prime is 261722653. The reversal of 261722645 is 546227162.

261722645 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 261722645 - 2¹⁴ = 261706261 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49856 + ... + 54854.

It is an arithmetic number, because the mean of its divisors is an integer number (20235000).

Almost surely, 2^261722645 is an apocalyptic number.

It is an amenable number.

261722645 is a deficient number, since it is larger than the sum of its proper divisors (62037355).

261722645 is a wasteful number, since it uses less digits than its factorization.

261722645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5324.

The product of its digits is 40320, while the sum is 35.

The square root of 261722645 is about 16177.8442630655. The cubic root of 261722645 is about 639.6569165400.

The spelling of 261722645 in words is "two hundred sixty-one million, seven hundred twenty-two thousand, six hundred forty-five".