61431240 has 128 divisors (see below), whose sum is σ = 202487040. Its totient is φ = 14816256.

The previous prime is 61431239. The next prime is 61431247. The reversal of 61431240 is 4213416.

It is a super-3 number, since 3×61431240³ (a number of 24 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (61431247) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 82309 + ... + 83051.

It is an arithmetic number, because the mean of its divisors is an integer number (1581930).

Almost surely, 2^61431240 is an apocalyptic number.

61431240 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 61431240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101243520).

61431240 is an abundant number, since it is smaller than the sum of its proper divisors (141055800).

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

61431240 is a wasteful number, since it uses less digits than its factorization.

61431240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 823 (or 819 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 61431240 is about 7837.8083671394. The cubic root of 61431240 is about 394.5751775139.

Adding to 61431240 its reverse (4213416), we get a palindrome (65644656).

The spelling of 61431240 in words is "sixty-one million, four hundred thirty-one thousand, two hundred forty".