551551661 has 16 divisors (see below), whose sum is σ = 582768000. Its totient is φ = 520986048.

The previous prime is 551551613. The next prime is 551551681. The reversal of 551551661 is 166155155.

It is a cyclic number.

It is not a de Polignac number, because 551551661 - 2¹⁴ = 551535277 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (551551681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 777575 + ... + 778283.

It is an arithmetic number, because the mean of its divisors is an integer number (36423000).

Almost surely, 2^551551661 is an apocalyptic number.

It is an amenable number.

551551661 is a deficient number, since it is larger than the sum of its proper divisors (31216339).

551551661 is a wasteful number, since it uses less digits than its factorization.

551551661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1108.

The product of its digits is 22500, while the sum is 35.

The square root of 551551661 is about 23485.1370232324. The cubic root of 551551661 is about 820.0910373841.

The spelling of 551551661 in words is "five hundred fifty-one million, five hundred fifty-one thousand, six hundred sixty-one".