21402142521 has 16 divisors (see below), whose sum is σ = 28995143424. Its totient is φ = 14039104464.

The previous prime is 21402142453. The next prime is 21402142529. The reversal of 21402142521 is 12524120412.

It is not a de Polignac number, because 21402142521 - 2²¹ = 21400045369 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21402142491 and 21402142500.

It is not an unprimeable number, because it can be changed into a prime (21402142529) 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, 117190 + ... + 237776.

It is an arithmetic number, because the mean of its divisors is an integer number (1812196464).

Almost surely, 2^21402142521 is an apocalyptic number.

It is an amenable number.

21402142521 is a deficient number, since it is larger than the sum of its proper divisors (7593000903).

21402142521 is a wasteful number, since it uses less digits than its factorization.

21402142521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121540.

The product of its (nonzero) digits is 1280, while the sum is 24.

Adding to 21402142521 its reverse (12524120412), we get a palindrome (33926262933).

The spelling of 21402142521 in words is "twenty-one billion, four hundred two million, one hundred forty-two thousand, five hundred twenty-one".