61909638 has 48 divisors (see below), whose sum is σ = 151629120. Its totient is φ = 16755984.

The previous prime is 61909609. The next prime is 61909643. The reversal of 61909638 is 83690916.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a self number, because there is not a number n which added to its sum of digits gives 61909638.

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, 45 + ... + 11127.

It is an arithmetic number, because the mean of its divisors is an integer number (3158940).

Almost surely, 2^61909638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61909638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75814560).

61909638 is an abundant number, since it is smaller than the sum of its proper divisors (89719482).

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

61909638 is a wasteful number, since it uses less digits than its factorization.

61909638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11121 (or 11114 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 42.

The square root of 61909638 is about 7868.2677890372. The cubic root of 61909638 is about 395.5967862951.

The spelling of 61909638 in words is "sixty-one million, nine hundred nine thousand, six hundred thirty-eight".