261752055021 has 24 divisors (see below), whose sum is σ = 379042664000. Its totient is φ = 174060176832.

The previous prime is 261752055001. The next prime is 261752055029. The reversal of 261752055021 is 120550257162.

261752055021 is a `hidden beast` number, since 2 + 61 + 7 + 5 + 20 + 550 + 21 = 666.

It is not a de Polignac number, because 261752055021 - 2²¹ = 261749957869 is a prime.

It is a super-2 number, since 2×261752055021² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261752055029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26146665 + ... + 26156673.

Almost surely, 2^261752055021 is an apocalyptic number.

It is an amenable number.

261752055021 is a deficient number, since it is larger than the sum of its proper divisors (117290608979).

261752055021 is a wasteful number, since it uses less digits than its factorization.

261752055021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17073 (or 17070 counting only the distinct ones).

The product of its (nonzero) digits is 42000, while the sum is 36.

The spelling of 261752055021 in words is "two hundred sixty-one billion, seven hundred fifty-two million, fifty-five thousand, twenty-one".