129777664 has 45 divisors (see below), whose sum is σ = 262496437. Its totient is φ = 64159744.

The previous prime is 129777649. The next prime is 129777667. The reversal of 129777664 is 466777921.

The square root of 129777664 is 11392.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 24920064 + 104857600 = 4992^2 + 10240^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129777667) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1458132 + ... + 1458220.

Almost surely, 2^129777664 is an apocalyptic number.

129777664 is the 11392-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 129777664

129777664 is an abundant number, since it is smaller than the sum of its proper divisors (132718773).

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

129777664 is an frugal number, since it uses more digits than its factorization.

129777664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206 (or 91 counting only the distinct ones).

The product of its digits is 889056, while the sum is 49.

The cubic root of 129777664 is about 506.2907399211.

Multiplying 129777664 by its sum of digits (49), we get a square (6359105536 = 79744²).

It can be divided in two parts, 1297 and 77664, that added together give a square (78961 = 281²).

The spelling of 129777664 in words is "one hundred twenty-nine million, seven hundred seventy-seven thousand, six hundred sixty-four".