15661481 has 8 divisors (see below), whose sum is σ = 17449344. Its totient is φ = 13934320.

The previous prime is 15661469. The next prime is 15661487. The reversal of 15661481 is 18416651.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 15661481 - 2¹⁸ = 15399337 is a prime.

It is a super-2 number, since 2×15661481² = 490563974226722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (15661487) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14630 + ... + 15663.

It is an arithmetic number, because the mean of its divisors is an integer number (2181168).

Almost surely, 2^15661481 is an apocalyptic number.

15661481 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15661481 is a deficient number, since it is larger than the sum of its proper divisors (1787863).

15661481 is a wasteful number, since it uses less digits than its factorization.

15661481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30351.

The product of its digits is 5760, while the sum is 32.

The square root of 15661481 is about 3957.4589069250. The cubic root of 15661481 is about 250.1944141068.

The spelling of 15661481 in words is "fifteen million, six hundred sixty-one thousand, four hundred eighty-one".