61812195840 has 240 divisors, whose sum is σ = 226666985688. Its totient is φ = 15513550848.

The previous prime is 61812195827. The next prime is 61812195877. The reversal of 61812195840 is 4859121816.

It is a happy number.

61812195840 is a `hidden beast` number, since 61 + 8 + 1 + 2 + 1 + 9 + 584 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 61511936256 + 300259584 = 248016^2 + 17328^2 .

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 312774 + ... + 470586.

Almost surely, 2^61812195840 is an apocalyptic number.

61812195840 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 61812195840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113333492844).

61812195840 is an abundant number, since it is smaller than the sum of its proper divisors (164854789848).

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

61812195840 is a wasteful number, since it uses less digits than its factorization.

61812195840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157859 (or 157840 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The spelling of 61812195840 in words is "sixty-one billion, eight hundred twelve million, one hundred ninety-five thousand, eight hundred forty".