61431231 has 4 divisors (see below), whose sum is σ = 81908312. Its totient is φ = 40954152.

The previous prime is 61431221. The next prime is 61431233. The reversal of 61431231 is 13213416.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 61431231 - 2⁷ = 61431103 is a prime.

It is a super-2 number, since 2×61431231² = 7547592284350722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61431198 and 61431207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61431233) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10238536 + ... + 10238541.

It is an arithmetic number, because the mean of its divisors is an integer number (20477078).

Almost surely, 2^61431231 is an apocalyptic number.

61431231 is a deficient number, since it is larger than the sum of its proper divisors (20477081).

61431231 is a wasteful number, since it uses less digits than its factorization.

61431231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20477080.

The product of its digits is 432, while the sum is 21.

The square root of 61431231 is about 7837.8077929993. The cubic root of 61431231 is about 394.5751582448.

Adding to 61431231 its reverse (13213416), we get a palindrome (74644647).

The spelling of 61431231 in words is "sixty-one million, four hundred thirty-one thousand, two hundred thirty-one".