771215940 has 144 divisors (see below), whose sum is σ = 2563456896. Its totient is φ = 186124800.

The previous prime is 771215917. The next prime is 771215941. The reversal of 771215940 is 49512177.

It is a happy number.

It is a super-2 number, since 2×771215940² = 1189548052220167200, which contains 22 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 = 771215895 and 771215904.

It is not an unprimeable number, because it can be changed into a prime (771215941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 520000 + ... + 521480.

It is an arithmetic number, because the mean of its divisors is an integer number (17801784).

Almost surely, 2^771215940 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 771215940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1281728448).

771215940 is an abundant number, since it is smaller than the sum of its proper divisors (1792240956).

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

771215940 is a wasteful number, since it uses less digits than its factorization.

771215940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1770 (or 1765 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 36.

The square root of 771215940 is about 27770.7749261701. The cubic root of 771215940 is about 917.0478543938.

The spelling of 771215940 in words is "seven hundred seventy-one million, two hundred fifteen thousand, nine hundred forty".