15501320440 has 16 divisors (see below), whose sum is σ = 34877971080. Its totient is φ = 6200528160.

The previous prime is 15501320437. The next prime is 15501320473. The reversal of 15501320440 is 4402310551.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 193766466 + ... + 193766545.

Almost surely, 2^15501320440 is an apocalyptic number.

15501320440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

15501320440 is an abundant number, since it is smaller than the sum of its proper divisors (19376650640).

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

15501320440 is a wasteful number, since it uses less digits than its factorization.

15501320440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 387533022 (or 387533018 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

Adding to 15501320440 its reverse (4402310551), we get a palindrome (19903630991).

The spelling of 15501320440 in words is "fifteen billion, five hundred one million, three hundred twenty thousand, four hundred forty".