261443971077408 has 192 divisors, whose sum is σ = 899592159191040. Its totient is φ = 72288655545600.

The previous prime is 261443971077329. The next prime is 261443971077409. The reversal of 261443971077408 is 804770179344162.

It is a happy number.

261443971077408 is a `hidden beast` number, since 2 + 6 + 144 + 3 + 9 + 7 + 10 + 77 + 408 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (261443971077409) 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, 697041058 + ... + 697416033.

It is an arithmetic number, because the mean of its divisors is an integer number (4685375829120).

Almost surely, 2^{261443971077408} is an apocalyptic number.

261443971077408 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

261443971077408 is an abundant number, since it is smaller than the sum of its proper divisors (638148188113632).

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

261443971077408 is a wasteful number, since it uses less digits than its factorization.

261443971077408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1394457148 (or 1394457134 counting only the distinct ones).

The product of its (nonzero) digits is 56899584, while the sum is 63.

The spelling of 261443971077408 in words is "two hundred sixty-one trillion, four hundred forty-three billion, nine hundred seventy-one million, seventy-seven thousand, four hundred eight".