21655054561465 has 32 divisors (see below), whose sum is σ = 28198361600640. Its totient is φ = 15869598603264.

The previous prime is 21655054561463. The next prime is 21655054561493. The reversal of 21655054561465 is 56416545055612.

It is a cyclic number.

It is not a de Polignac number, because 21655054561465 - 2¹ = 21655054561463 is a prime.

It is a super-2 number, since 2×21655054561465² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21655054561463) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 20694537 + ... + 21715753.

It is an arithmetic number, because the mean of its divisors is an integer number (881198800020).

Almost surely, 2^{21655054561465} is an apocalyptic number.

It is an amenable number.

21655054561465 is a deficient number, since it is larger than the sum of its proper divisors (6543307039175).

21655054561465 is a wasteful number, since it uses less digits than its factorization.

21655054561465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1023721.

The product of its (nonzero) digits is 21600000, while the sum is 55.

The spelling of 21655054561465 in words is "twenty-one trillion, six hundred fifty-five billion, fifty-four million, five hundred sixty-one thousand, four hundred sixty-five".