21001251403535 has 16 divisors (see below), whose sum is σ = 27146832017760. Its totient is φ = 15504757403520.

The previous prime is 21001251403529. The next prime is 21001251403537. The reversal of 21001251403535 is 53530415210012.

It is not a de Polignac number, because 21001251403535 - 2¹⁶ = 21001251337999 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001251403537) 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, 39934856 + ... + 40457325.

It is an arithmetic number, because the mean of its divisors is an integer number (1696677001110).

Almost surely, 2^{21001251403535} is an apocalyptic number.

21001251403535 is a deficient number, since it is larger than the sum of its proper divisors (6145580614225).

21001251403535 is a wasteful number, since it uses less digits than its factorization.

21001251403535 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80396218.

The product of its (nonzero) digits is 18000, while the sum is 32.

Adding to 21001251403535 its reverse (53530415210012), we get a palindrome (74531666613547).

The spelling of 21001251403535 in words is "twenty-one trillion, one billion, two hundred fifty-one million, four hundred three thousand, five hundred thirty-five".