772721640 has 128 divisors (see below), whose sum is σ = 2711376000. Its totient is φ = 195208704.

The previous prime is 772721603. The next prime is 772721647. The reversal of 772721640 is 46127277.

It is a happy number.

772721640 is a `hidden beast` number, since 7 + 7 + 2 + 7 + 2 + 1 + 640 = 666.

It is a super-3 number, since 3×772721640³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 772721595 and 772721604.

It is not an unprimeable number, because it can be changed into a prime (772721647) 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, 1692 + ... + 39348.

It is an arithmetic number, because the mean of its divisors is an integer number (21182625).

Almost surely, 2^772721640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 772721640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1355688000).

772721640 is an abundant number, since it is smaller than the sum of its proper divisors (1938654360).

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

772721640 is a wasteful number, since it uses less digits than its factorization.

772721640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37696 (or 37686 counting only the distinct ones).

The product of its (nonzero) digits is 32928, while the sum is 36.

The square root of 772721640 is about 27797.8711415101. The cubic root of 772721640 is about 917.6442724419.

The spelling of 772721640 in words is "seven hundred seventy-two million, seven hundred twenty-one thousand, six hundred forty".