661528155800 has 24 divisors (see below), whose sum is σ = 1538052962700. Its totient is φ = 264611262240.

The previous prime is 661528155781. The next prime is 661528155809. The reversal of 661528155800 is 8551825166.

It is a super-2 number, since 2×661528155800² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661528155809) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1653820190 + ... + 1653820589.

Almost surely, 2^661528155800 is an apocalyptic number.

It is an amenable number.

661528155800 is an abundant number, since it is smaller than the sum of its proper divisors (876524806900).

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

661528155800 is a wasteful number, since it uses less digits than its factorization.

661528155800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3307640795 (or 3307640786 counting only the distinct ones).

The product of its (nonzero) digits is 576000, while the sum is 47.

The spelling of 661528155800 in words is "six hundred sixty-one billion, five hundred twenty-eight million, one hundred fifty-five thousand, eight hundred".