537199981 has 4 divisors (see below), whose sum is σ = 540805500. Its totient is φ = 533594464.

The previous prime is 537199969. The next prime is 537200009. The reversal of 537199981 is 189991735.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 223024356 + 314175625 = 14934^2 + 17725^2 .

It is a cyclic number.

It is not a de Polignac number, because 537199981 - 2¹⁹ = 536675693 is a prime.

It is a super-2 number, since 2×537199981² = 577167639172800722, 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 (537199951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1802536 + ... + 1802833.

It is an arithmetic number, because the mean of its divisors is an integer number (135201375).

Almost surely, 2^537199981 is an apocalyptic number.

It is an amenable number.

537199981 is a deficient number, since it is larger than the sum of its proper divisors (3605519).

537199981 is a wasteful number, since it uses less digits than its factorization.

537199981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3605518.

The product of its digits is 612360, while the sum is 52.

The square root of 537199981 is about 23177.5749594301. The cubic root of 537199981 is about 812.9153598871.

The spelling of 537199981 in words is "five hundred thirty-seven million, one hundred ninety-nine thousand, nine hundred eighty-one".