21172214516 has 12 divisors (see below), whose sum is σ = 37955067780. Its totient is φ = 10327909440.

The previous prime is 21172214513. The next prime is 21172214519. The reversal of 21172214516 is 61541227112.

It is an interprime number because it is at equal distance from previous prime (21172214513) and next prime (21172214519).

It can be written as a sum of positive squares in 2 ways, for example, as 1557091600 + 19615122916 = 39460^2 + 140054^2 .

It is a super-2 number, since 2×21172214516² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21172214513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64549271 + ... + 64549598.

It is an arithmetic number, because the mean of its divisors is an integer number (3162922315).

Almost surely, 2^21172214516 is an apocalyptic number.

It is an amenable number.

21172214516 is a deficient number, since it is larger than the sum of its proper divisors (16782853264).

21172214516 is a wasteful number, since it uses less digits than its factorization.

21172214516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129098914 (or 129098912 counting only the distinct ones).

The product of its digits is 6720, while the sum is 32.

The spelling of 21172214516 in words is "twenty-one billion, one hundred seventy-two million, two hundred fourteen thousand, five hundred sixteen".