15541981 has 32 divisors (see below), whose sum is σ = 20563200. Its totient is φ = 11404800.

The previous prime is 15541973. The next prime is 15541987. The reversal of 15541981 is 18914551.

It is a cyclic number.

It is not a de Polignac number, because 15541981 - 2³ = 15541973 is a prime.

It is a super-2 number, since 2×15541981² = 483106346808722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15541987) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 153831 + ... + 153931.

It is an arithmetic number, because the mean of its divisors is an integer number (642600).

Almost surely, 2^15541981 is an apocalyptic number.

It is an amenable number.

15541981 is a deficient number, since it is larger than the sum of its proper divisors (5021219).

15541981 is a wasteful number, since it uses less digits than its factorization.

15541981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229.

The product of its digits is 7200, while the sum is 34.

The square root of 15541981 is about 3942.3319241282. The cubic root of 15541981 is about 249.5564455030.

The spelling of 15541981 in words is "fifteen million, five hundred forty-one thousand, nine hundred eighty-one".