551661511506 has 48 divisors (see below), whose sum is σ = 1288025051040. Its totient is φ = 157056634560.

The previous prime is 551661511493. The next prime is 551661511517. The reversal of 551661511506 is 605115166155.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3256176 + ... + 3421403.

It is an arithmetic number, because the mean of its divisors is an integer number (26833855230).

Almost surely, 2^551661511506 is an apocalyptic number.

551661511506 is an abundant number, since it is smaller than the sum of its proper divisors (736363539534).

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

551661511506 is a wasteful number, since it uses less digits than its factorization.

551661511506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6677879 (or 6677872 counting only the distinct ones).

The product of its (nonzero) digits is 135000, while the sum is 42.

The spelling of 551661511506 in words is "five hundred fifty-one billion, six hundred sixty-one million, five hundred eleven thousand, five hundred six".