1539981 has 12 divisors (see below), whose sum is σ = 2242240. Its totient is φ = 1018440.

The previous prime is 1539973. The next prime is 1539983. The reversal of 1539981 is 1899351.

It is a happy number.

It is not a de Polignac number, because 1539981 - 2³ = 1539973 is a prime.

It is a super-2 number, since 2×1539981² = 4743082960722, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

1539981 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1539983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 636 + ... + 1866.

2^1539981 is an apocalyptic number.

It is an amenable number.

1539981 is a deficient number, since it is larger than the sum of its proper divisors (702259).

1539981 is a wasteful number, since it uses less digits than its factorization.

1539981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1376 (or 1373 counting only the distinct ones).

The product of its digits is 9720, while the sum is 36.

The square root of 1539981 is about 1240.9597092573. The cubic root of 1539981 is about 115.4795601093.

The spelling of 1539981 in words is "one million, five hundred thirty-nine thousand, nine hundred eighty-one".