15621535512642 has 16 divisors (see below), whose sum is σ = 31552408363392. Its totient is φ = 5155622281200.

The previous prime is 15621535512637. The next prime is 15621535512673. The reversal of 15621535512642 is 24621553512651.

It is a junction number, because it is equal to n+sod(n) for n = 15621535512591 and 15621535512600.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12889055098 + ... + 12889056309.

It is an arithmetic number, because the mean of its divisors is an integer number (1972025522712).

Almost surely, 2^{15621535512642} is an apocalyptic number.

15621535512642 is an abundant number, since it is smaller than the sum of its proper divisors (15930872850750).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15621535512642 is a wasteful number, since it uses less digits than its factorization.

15621535512642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25778111513.

The product of its digits is 2160000, while the sum is 48.

Subtracting 15621535512642 from its reverse (24621553512651), we obtain a square (9000018000009 = 3000003²).

The spelling of 15621535512642 in words is "fifteen trillion, six hundred twenty-one billion, five hundred thirty-five million, five hundred twelve thousand, six hundred forty-two".