61431940 has 48 divisors (see below), whose sum is σ = 139144320. Its totient is φ = 22705920.

The previous prime is 61431917. The next prime is 61431949. The reversal of 61431940 is 4913416.

It is a junction number, because it is equal to n+sod(n) for n = 61431899 and 61431908.

It is not an unprimeable number, because it can be changed into a prime (61431949) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13609 + ... + 17551.

It is an arithmetic number, because the mean of its divisors is an integer number (2898840).

Almost surely, 2^61431940 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 61431940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69572160).

61431940 is an abundant number, since it is smaller than the sum of its proper divisors (77712380).

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

61431940 is a wasteful number, since it uses less digits than its factorization.

61431940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4012 (or 4010 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 61431940 is about 7837.8530223525. The cubic root of 61431940 is about 394.5766762170.

The spelling of 61431940 in words is "sixty-one million, four hundred thirty-one thousand, nine hundred forty".