21002150251 has 16 divisors (see below), whose sum is σ = 23414896800. Its totient is φ = 18720834048.

The previous prime is 21002150219. The next prime is 21002150263. The reversal of 21002150251 is 15205120012.

It is a cyclic number.

It is not a de Polignac number, because 21002150251 - 2⁵ = 21002150219 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21002150051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1405045 + ... + 1419913.

It is an arithmetic number, because the mean of its divisors is an integer number (1463431050).

Almost surely, 2^21002150251 is an apocalyptic number.

21002150251 is a deficient number, since it is larger than the sum of its proper divisors (2412746549).

21002150251 is a wasteful number, since it uses less digits than its factorization.

21002150251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19278.

The product of its (nonzero) digits is 200, while the sum is 19.

Adding to 21002150251 its reverse (15205120012), we get a palindrome (36207270263).

The spelling of 21002150251 in words is "twenty-one billion, two million, one hundred fifty thousand, two hundred fifty-one".