61271321664 has 168 divisors, whose sum is σ = 199674784800. Its totient is φ = 16476278784.

The previous prime is 61271321663. The next prime is 61271321693. The reversal of 61271321664 is 46612317216.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (168).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (61271321663) 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, 31614 + ... + 351485.

Almost surely, 2^61271321664 is an apocalyptic number.

61271321664 is a gapful number since it is divisible by the number (64) 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 61271321664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99837392400).

61271321664 is an abundant number, since it is smaller than the sum of its proper divisors (138403463136).

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

61271321664 is a wasteful number, since it uses less digits than its factorization.

61271321664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 383145 (or 383128 counting only the distinct ones).

The product of its digits is 72576, while the sum is 39.

The spelling of 61271321664 in words is "sixty-one billion, two hundred seventy-one million, three hundred twenty-one thousand, six hundred sixty-four".