981671557 has 2 divisors, whose sum is σ = 981671558. Its totient is φ = 981671556.

The previous prime is 981671543. The next prime is 981671633. The reversal of 981671557 is 755176189.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 857259841 + 124411716 = 29279^2 + 11154^2 .

It is an emirp because it is prime and its reverse (755176189) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 981671557 - 2⁷ = 981671429 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 981671557.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (981671507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 490835778 + 490835779.

It is an arithmetic number, because the mean of its divisors is an integer number (490835779).

Almost surely, 2^981671557 is an apocalyptic number.

It is an amenable number.

981671557 is a deficient number, since it is larger than the sum of its proper divisors (1).

981671557 is an equidigital number, since it uses as much as digits as its factorization.

981671557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 529200, while the sum is 49.

The square root of 981671557 is about 31331.6382750727. The cubic root of 981671557 is about 993.8528084662.

The spelling of 981671557 in words is "nine hundred eighty-one million, six hundred seventy-one thousand, five hundred fifty-seven".