61400643640 has 48 divisors (see below), whose sum is σ = 160706791800. Its totient is φ = 21051648576.

The previous prime is 61400643589. The next prime is 61400643641. The reversal of 61400643640 is 4634600416.

61400643640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 61400643596 and 61400643605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61400643641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15661470 + ... + 15665389.

Almost surely, 2^61400643640 is an apocalyptic number.

It is an amenable number.

61400643640 is an abundant number, since it is smaller than the sum of its proper divisors (99306148160).

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

61400643640 is a wasteful number, since it uses less digits than its factorization.

61400643640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31326884 (or 31326873 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 34.

The spelling of 61400643640 in words is "sixty-one billion, four hundred million, six hundred forty-three thousand, six hundred forty".