55781559 has 6 divisors (see below), whose sum is σ = 80573376. Its totient is φ = 37187700.

The previous prime is 55781543. The next prime is 55781567. The reversal of 55781559 is 95518755.

It is not a de Polignac number, because 55781559 - 2⁴ = 55781543 is a prime.

It is a super-2 number, since 2×55781559² = 6223164648940962, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55781519) 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, 3098967 + ... + 3098984.

It is an arithmetic number, because the mean of its divisors is an integer number (13428896).

Almost surely, 2^55781559 is an apocalyptic number.

55781559 is a deficient number, since it is larger than the sum of its proper divisors (24791817).

55781559 is a wasteful number, since it uses less digits than its factorization.

55781559 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6197957 (or 6197954 counting only the distinct ones).

The product of its digits is 315000, while the sum is 45.

The square root of 55781559 is about 7468.7053094897. The cubic root of 55781559 is about 382.0881328588.

The spelling of 55781559 in words is "fifty-five million, seven hundred eighty-one thousand, five hundred fifty-nine".