61409665920 has 256 divisors, whose sum is σ = 206973504000. Its totient is φ = 15444172800.

The previous prime is 61409665907. The next prime is 61409665931. The reversal of 61409665920 is 2956690416.

It is a super-2 number, since 2×61409665920² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 61409665920.

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, 8350245 + ... + 8357595.

It is an arithmetic number, because the mean of its divisors is an integer number (808490250).

Almost surely, 2^61409665920 is an apocalyptic number.

61409665920 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61409665920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103486752000).

61409665920 is an abundant number, since it is smaller than the sum of its proper divisors (145563838080).

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

61409665920 is a wasteful number, since it uses less digits than its factorization.

61409665920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7621 (or 7609 counting only the distinct ones).

The product of its (nonzero) digits is 699840, while the sum is 48.

The spelling of 61409665920 in words is "sixty-one billion, four hundred nine million, six hundred sixty-five thousand, nine hundred twenty".