77621940 has 144 divisors (see below), whose sum is σ = 259459200. Its totient is φ = 18627840.

The previous prime is 77621927. The next prime is 77621959. The reversal of 77621940 is 4912677.

It is a happy number.

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 = 77621895 and 77621904.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 389961 + ... + 390159.

It is an arithmetic number, because the mean of its divisors is an integer number (1801800).

Almost surely, 2^77621940 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 77621940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129729600).

77621940 is an abundant number, since it is smaller than the sum of its proper divisors (181837260).

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

77621940 is a wasteful number, since it uses less digits than its factorization.

77621940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422 (or 417 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 77621940 is about 8810.3314353093. The cubic root of 77621940 is about 426.5744416010.

The spelling of 77621940 in words is "seventy-seven million, six hundred twenty-one thousand, nine hundred forty".