661255346420 has 24 divisors (see below), whose sum is σ = 1388856526848. Its totient is φ = 264460176800.

The previous prime is 661255346407. The next prime is 661255346429. The reversal of 661255346420 is 24643552166.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661255346429) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2493236 + ... + 2745675.

It is an arithmetic number, because the mean of its divisors is an integer number (57869021952).

Almost surely, 2^661255346420 is an apocalyptic number.

It is an amenable number.

661255346420 is an abundant number, since it is smaller than the sum of its proper divisors (727601180428).

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

661255346420 is a wasteful number, since it uses less digits than its factorization.

661255346420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5245231 (or 5245229 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 44.

Adding to 661255346420 its reverse (24643552166), we get a palindrome (685898898586).

The spelling of 661255346420 in words is "six hundred sixty-one billion, two hundred fifty-five million, three hundred forty-six thousand, four hundred twenty".