21154042424 has 8 divisors (see below), whose sum is σ = 39663829560. Its totient is φ = 10577021208.

The previous prime is 21154042409. The next prime is 21154042439. The reversal of 21154042424 is 42424045112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21154042409) and next prime (21154042439).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1322127644 + ... + 1322127659.

It is an arithmetic number, because the mean of its divisors is an integer number (4957978695).

Almost surely, 2^21154042424 is an apocalyptic number.

It is an amenable number.

21154042424 is a deficient number, since it is larger than the sum of its proper divisors (18509787136).

21154042424 is a wasteful number, since it uses less digits than its factorization.

21154042424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2644255309 (or 2644255305 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 29.

Adding to 21154042424 its reverse (42424045112), we get a palindrome (63578087536).

The spelling of 21154042424 in words is "twenty-one billion, one hundred fifty-four million, forty-two thousand, four hundred twenty-four".