15660342621 has 72 divisors (see below), whose sum is σ = 30216794400. Its totient is φ = 7707026880.

The previous prime is 15660342617. The next prime is 15660342629. The reversal of 15660342621 is 12624306651.

15660342621 is a `hidden beast` number, since 1 + 5 + 6 + 603 + 4 + 26 + 21 = 666.

It is not a de Polignac number, because 15660342621 - 2² = 15660342617 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15660342629) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 7215 + ... + 177123.

It is an arithmetic number, because the mean of its divisors is an integer number (419677700).

Almost surely, 2^15660342621 is an apocalyptic number.

15660342621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

15660342621 is a deficient number, since it is larger than the sum of its proper divisors (14556451779).

15660342621 is a wasteful number, since it uses less digits than its factorization.

15660342621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169959 (or 169949 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

It can be divided in two parts, 15660 and 342621, that added together give a triangular number (358281 = T₈₄₆).

The spelling of 15660342621 in words is "fifteen billion, six hundred sixty million, three hundred forty-two thousand, six hundred twenty-one".