1555551988 has 6 divisors (see below), whose sum is σ = 2722215986. Its totient is φ = 777775992.

The previous prime is 1555551953. The next prime is 1555551989. The reversal of 1555551988 is 8891555551.

It can be written as a sum of positive squares in only one way, i.e., 950982244 + 604569744 = 30838^2 + 24588^2 .

It is a super-5 number, since 5×1555551988⁵ (a number of 47 digits) contains 55555 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1555551989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 194443995 + ... + 194444002.

Almost surely, 2^1555551988 is an apocalyptic number.

It is an amenable number.

1555551988 is a deficient number, since it is larger than the sum of its proper divisors (1166663998).

1555551988 is a wasteful number, since it uses less digits than its factorization.

1555551988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388888001 (or 388887999 counting only the distinct ones).

The product of its digits is 1800000, while the sum is 52.

The square root of 1555551988 is about 39440.4866602835. The cubic root of 1555551988 is about 1158.6746625149.

The spelling of 1555551988 in words is "one billion, five hundred fifty-five million, five hundred fifty-one thousand, nine hundred eighty-eight".