15621466661 has 8 divisors (see below), whose sum is σ = 15649438464. Its totient is φ = 15593520880.

The previous prime is 15621466643. The next prime is 15621466681. The reversal of 15621466661 is 16666412651.

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 15621466661 - 2¹⁸ = 15621204517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15621466631) 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, 1484360 + ... + 1494846.

It is an arithmetic number, because the mean of its divisors is an integer number (1956179808).

Almost surely, 2^15621466661 is an apocalyptic number.

It is an amenable number.

15621466661 is a deficient number, since it is larger than the sum of its proper divisors (27971803).

15621466661 is a wasteful number, since it uses less digits than its factorization.

15621466661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13011.

The product of its digits is 311040, while the sum is 44.

The spelling of 15621466661 in words is "fifteen billion, six hundred twenty-one million, four hundred sixty-six thousand, six hundred sixty-one".