261851970 has 32 divisors (see below), whose sum is σ = 633251520. Its totient is φ = 69293120.

The previous prime is 261851963. The next prime is 261851981. The reversal of 261851970 is 79158162.

It is a super-5 number, since 5×261851970⁵ (a number of 43 digits) contains 55555 as substring.

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, 29385 + ... + 37244.

It is an arithmetic number, because the mean of its divisors is an integer number (19789110).

Almost surely, 2^261851970 is an apocalyptic number.

261851970 is an abundant number, since it is smaller than the sum of its proper divisors (371399550).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261851970 is a wasteful number, since it uses less digits than its factorization.

261851970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66770.

The product of its (nonzero) digits is 30240, while the sum is 39.

The square root of 261851970 is about 16181.8407481967. The cubic root of 261851970 is about 639.7622570734.

The spelling of 261851970 in words is "two hundred sixty-one million, eight hundred fifty-one thousand, nine hundred seventy".