21555155415 has 16 divisors (see below), whose sum is σ = 34570569600. Its totient is φ = 11468642592.

The previous prime is 21555155393. The next prime is 21555155417. The reversal of 21555155415 is 51455155512.

It is not a de Polignac number, because 21555155415 - 2²² = 21550961111 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21555155417) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1708525 + ... + 1721094.

It is an arithmetic number, because the mean of its divisors is an integer number (2160660600).

Almost surely, 2^21555155415 is an apocalyptic number.

21555155415 is a deficient number, since it is larger than the sum of its proper divisors (13015414185).

21555155415 is a wasteful number, since it uses less digits than its factorization.

21555155415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3430046.

The product of its digits is 125000, while the sum is 39.

The spelling of 21555155415 in words is "twenty-one billion, five hundred fifty-five million, one hundred fifty-five thousand, four hundred fifteen".