21424804621544 has 8 divisors (see below), whose sum is σ = 40171508665410. Its totient is φ = 10712402310768.

The previous prime is 21424804621513. The next prime is 21424804621559. The reversal of 21424804621544 is 44512640842412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18717996544900 + 2706808076644 = 4326430^2 + 1645238^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1339050288839 + ... + 1339050288854.

Almost surely, 2^{21424804621544} is an apocalyptic number.

It is an amenable number.

21424804621544 is a deficient number, since it is larger than the sum of its proper divisors (18746704043866).

21424804621544 is a wasteful number, since it uses less digits than its factorization.

21424804621544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2678100577699 (or 2678100577695 counting only the distinct ones).

The product of its (nonzero) digits is 1966080, while the sum is 47.

The spelling of 21424804621544 in words is "twenty-one trillion, four hundred twenty-four billion, eight hundred four million, six hundred twenty-one thousand, five hundred forty-four".