21006213371 has 8 divisors (see below), whose sum is σ = 24678628464. Its totient is φ = 17627591520.

The previous prime is 21006213367. The next prime is 21006213377. The reversal of 21006213371 is 17331260012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21006213371 - 2² = 21006213367 is a prime.

It is a super-2 number, since 2×21006213371² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21006213371.

It is not an unprimeable number, because it can be changed into a prime (21006213377) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 73448156 + ... + 73448441.

It is an arithmetic number, because the mean of its divisors is an integer number (3084828558).

Almost surely, 2^21006213371 is an apocalyptic number.

21006213371 is a deficient number, since it is larger than the sum of its proper divisors (3672415093).

21006213371 is a wasteful number, since it uses less digits than its factorization.

21006213371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146896621.

The product of its (nonzero) digits is 1512, while the sum is 26.

Adding to 21006213371 its reverse (17331260012), we get a palindrome (38337473383).

The spelling of 21006213371 in words is "twenty-one billion, six million, two hundred thirteen thousand, three hundred seventy-one".