61439904 has 192 divisors, whose sum is σ = 195955200. Its totient is φ = 18653184.

The previous prime is 61439899. The next prime is 61439927. The reversal of 61439904 is 40993416.

61439904 is a `hidden beast` number, since 614 + 39 + 9 + 0 + 4 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 690292 + ... + 690380.

It is an arithmetic number, because the mean of its divisors is an integer number (1020600).

Almost surely, 2^61439904 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 61439904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97977600).

61439904 is an abundant number, since it is smaller than the sum of its proper divisors (134515296).

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

61439904 is a wasteful number, since it uses less digits than its factorization.

61439904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 61439904 is about 7838.3610531794. The cubic root of 61439904 is about 394.5937263751.

The spelling of 61439904 in words is "sixty-one million, four hundred thirty-nine thousand, nine hundred four".