1553387981 has 8 divisors (see below), whose sum is σ = 1574113920. Its totient is φ = 1532688768.

The previous prime is 1553387939. The next prime is 1553387999. The reversal of 1553387981 is 1897833551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1553387981 - 2¹⁴ = 1553371597 is a prime.

It is a super-2 number, since 2×1553387981² = 4826028439030512722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1553387281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 128270 + ... + 139856.

It is an arithmetic number, because the mean of its divisors is an integer number (196764240).

Almost surely, 2^1553387981 is an apocalyptic number.

It is an amenable number.

1553387981 is a deficient number, since it is larger than the sum of its proper divisors (20725939).

1553387981 is a wasteful number, since it uses less digits than its factorization.

1553387981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13363.

The product of its digits is 907200, while the sum is 50.

The square root of 1553387981 is about 39413.0432851867. The cubic root of 1553387981 is about 1158.1371162048.

The spelling of 1553387981 in words is "one billion, five hundred fifty-three million, three hundred eighty-seven thousand, nine hundred eighty-one".