261447535326720 has 1280 divisors, whose sum is σ = 901277914521600. Its totient is φ = 64505413632000.

The previous prime is 261447535326701. The next prime is 261447535326727. The reversal of 261447535326720 is 27623535744162.

It is a tau number, because it is divible by the number of its divisors (1280).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261447535326727) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 232811696079 + ... + 232811697201.

It is an arithmetic number, because the mean of its divisors is an integer number (704123370720).

Almost surely, 2^{261447535326720} is an apocalyptic number.

261447535326720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261447535326720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (450638957260800).

261447535326720 is an abundant number, since it is smaller than the sum of its proper divisors (639830379194880).

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

261447535326720 is a wasteful number, since it uses less digits than its factorization.

261447535326720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1571 (or 1555 counting only the distinct ones).

The product of its (nonzero) digits is 50803200, while the sum is 57.

The spelling of 261447535326720 in words is "two hundred sixty-one trillion, four hundred forty-seven billion, five hundred thirty-five million, three hundred twenty-six thousand, seven hundred twenty".