1055399981 has 2 divisors, whose sum is σ = 1055399982. Its totient is φ = 1055399980.

The previous prime is 1055399941. The next prime is 1055400007. The reversal of 1055399981 is 1899935501.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 649740100 + 405659881 = 25490^2 + 20141^2 .

It is an emirp because it is prime and its reverse (1899935501) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1055399981 - 2¹⁰ = 1055398957 is a prime.

It is a super-2 number, since 2×1055399981² = 2227738239789600722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1055399911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 527699990 + 527699991.

It is an arithmetic number, because the mean of its divisors is an integer number (527699991).

Almost surely, 2^1055399981 is an apocalyptic number.

It is an amenable number.

1055399981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1055399981 is an equidigital number, since it uses as much as digits as its factorization.

1055399981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 437400, while the sum is 50.

The square root of 1055399981 is about 32486.9201525783. The cubic root of 1055399981 is about 1018.1357660040.

The spelling of 1055399981 in words is "one billion, fifty-five million, three hundred ninety-nine thousand, nine hundred eighty-one".