21535003500424 has 8 divisors (see below), whose sum is σ = 40378131563310. Its totient is φ = 10767501750208.

The previous prime is 21535003500407. The next prime is 21535003500449. The reversal of 21535003500424 is 42400530053512.

It can be written as a sum of positive squares in only one way, i.e., 11416357016100 + 10118646484324 = 3378810^2 + 3180982^2 .

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

It is a self number, because there is not a number n which added to its sum of digits gives 21535003500424.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1345937718769 + ... + 1345937718784.

Almost surely, 2^{21535003500424} is an apocalyptic number.

It is an amenable number.

21535003500424 is a deficient number, since it is larger than the sum of its proper divisors (18843128062886).

21535003500424 is a wasteful number, since it uses less digits than its factorization.

21535003500424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2691875437559 (or 2691875437555 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 34.

Adding to 21535003500424 its reverse (42400530053512), we get a palindrome (63935533553936).

The spelling of 21535003500424 in words is "twenty-one trillion, five hundred thirty-five billion, three million, five hundred thousand, four hundred twenty-four".