21401034021 has 12 divisors (see below), whose sum is σ = 30914514540. Its totient is φ = 14266474560.

The previous prime is 21401034019. The next prime is 21401034059. The reversal of 21401034021 is 12043010412.

It can be written as a sum of positive squares in 2 ways, for example, as 21269013921 + 132020100 = 145839^2 + 11490^2 .

It is not a de Polignac number, because 21401034021 - 2¹ = 21401034019 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21401033985 and 21401034003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21401234021) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 102495 + ... + 230883.

It is an arithmetic number, because the mean of its divisors is an integer number (2576209545).

Almost surely, 2^21401034021 is an apocalyptic number.

It is an amenable number.

21401034021 is a deficient number, since it is larger than the sum of its proper divisors (9513480519).

21401034021 is a wasteful number, since it uses less digits than its factorization.

21401034021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146916 (or 146913 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21401034021 its reverse (12043010412), we get a palindrome (33444044433).

The spelling of 21401034021 in words is "twenty-one billion, four hundred one million, thirty-four thousand, twenty-one".