78921040 has 120 divisors (see below), whose sum is σ = 208986624. Its totient is φ = 27667200.

The previous prime is 78921013. The next prime is 78921047. The reversal of 78921040 is 4012987.

78921040 = T₁₂₅₆ + T₁₂₅₇ + ... + T₁₃₄₈.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a junction number, because it is equal to n+sod(n) for n = 78920993 and 78921011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78921047) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 299949 + ... + 300211.

Almost surely, 2^78921040 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 78921040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104493312).

78921040 is an abundant number, since it is smaller than the sum of its proper divisors (130065584).

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

78921040 is a wasteful number, since it uses less digits than its factorization.

78921040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329 (or 312 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 78921040 is about 8883.7514598282. The cubic root of 78921040 is about 428.9410394534.

The spelling of 78921040 in words is "seventy-eight million, nine hundred twenty-one thousand, forty".