61138836 has 72 divisors (see below), whose sum is σ = 171426528. Its totient is φ = 18216000.

The previous prime is 61138823. The next prime is 61138841. The reversal of 61138836 is 63883116.

61138836 is a `hidden beast` number, since 611 + 3 + 8 + 8 + 36 = 666.

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

It is a self number, because there is not a number n which added to its sum of digits gives 61138836.

It is a congruent number.

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, 22891 + ... + 25421.

It is an arithmetic number, because the mean of its divisors is an integer number (2380924).

Almost surely, 2^61138836 is an apocalyptic number.

61138836 is a gapful number since it is divisible by the number (66) 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 61138836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85713264).

61138836 is an abundant number, since it is smaller than the sum of its proper divisors (110287692).

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

61138836 is a wasteful number, since it uses less digits than its factorization.

61138836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2613 (or 2608 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 61138836 is about 7819.1326884764. The cubic root of 61138836 is about 393.9481409409.

The spelling of 61138836 in words is "sixty-one million, one hundred thirty-eight thousand, eight hundred thirty-six".