55643778 has 12 divisors (see below), whose sum is σ = 120561558. Its totient is φ = 18547920.

The previous prime is 55643747. The next prime is 55643801. The reversal of 55643778 is 87734655.

It can be written as a sum of positive squares in only one way, i.e., 50594769 + 5049009 = 7113^2 + 2247^2 .

It is a super-2 number, since 2×55643778² = 6192460060226568, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1545643 + ... + 1545678.

Almost surely, 2^55643778 is an apocalyptic number.

55643778 is an abundant number, since it is smaller than the sum of its proper divisors (64917780).

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

55643778 is a wasteful number, since it uses less digits than its factorization.

55643778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3091329 (or 3091326 counting only the distinct ones).

The product of its digits is 705600, while the sum is 45.

The square root of 55643778 is about 7459.4757188424. The cubic root of 55643778 is about 381.7732863415.

The spelling of 55643778 in words is "fifty-five million, six hundred forty-three thousand, seven hundred seventy-eight".