21142817667 has 16 divisors (see below), whose sum is σ = 31337435680. Its totient is φ = 14088577536.

The previous prime is 21142817651. The next prime is 21142817671. The reversal of 21142817667 is 76671824112.

21142817667 is a `hidden beast` number, since 211 + 428 + 1 + 7 + 6 + 6 + 7 = 666.

It is not a de Polignac number, because 21142817667 - 2⁴ = 21142817651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21142817617) 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, 125518 + ... + 240915.

It is an arithmetic number, because the mean of its divisors is an integer number (1958589730).

Almost surely, 2^21142817667 is an apocalyptic number.

21142817667 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21142817667 is a deficient number, since it is larger than the sum of its proper divisors (10194618013).

21142817667 is a wasteful number, since it uses less digits than its factorization.

21142817667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368579 (or 368573 counting only the distinct ones).

The product of its digits is 225792, while the sum is 45.

The spelling of 21142817667 in words is "twenty-one billion, one hundred forty-two million, eight hundred seventeen thousand, six hundred sixty-seven".