8129025661 has 16 divisors (see below), whose sum is σ = 8355916800. Its totient is φ = 7906158000.

The previous prime is 8129025659. The next prime is 8129025691. The reversal of 8129025661 is 1665209218.

It is a cyclic number.

It is not a de Polignac number, because 8129025661 - 2¹ = 8129025659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8129025691) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1435686 + ... + 1441336.

It is an arithmetic number, because the mean of its divisors is an integer number (522244800).

Almost surely, 2^8129025661 is an apocalyptic number.

It is an amenable number.

8129025661 is a deficient number, since it is larger than the sum of its proper divisors (226891139).

8129025661 is a wasteful number, since it uses less digits than its factorization.

8129025661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6000.

The product of its (nonzero) digits is 51840, while the sum is 40.

The square root of 8129025661 is about 90161.1094707690. The cubic root of 8129025661 is about 2010.6948466052.

The spelling of 8129025661 in words is "eight billion, one hundred twenty-nine million, twenty-five thousand, six hundred sixty-one".