21507535656354 has 32 divisors (see below), whose sum is σ = 46926606541824. Its totient is φ = 6517285852880.

The previous prime is 21507535656337. The next prime is 21507535656361. The reversal of 21507535656354 is 45365653570512.

It is a junction number, because it is equal to n+sod(n) for n = 21507535656294 and 21507535656303.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 807654 + ... + 6608129.

It is an arithmetic number, because the mean of its divisors is an integer number (1466456454432).

Almost surely, 2^{21507535656354} is an apocalyptic number.

21507535656354 is an abundant number, since it is smaller than the sum of its proper divisors (25419070885470).

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

21507535656354 is a wasteful number, since it uses less digits than its factorization.

21507535656354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7459742.

The product of its (nonzero) digits is 56700000, while the sum is 57.

The spelling of 21507535656354 in words is "twenty-one trillion, five hundred seven billion, five hundred thirty-five million, six hundred fifty-six thousand, three hundred fifty-four".