21234171657 has 32 divisors (see below), whose sum is σ = 30551385600. Its totient is φ = 13070573568.

The previous prime is 21234171643. The next prime is 21234171671. The reversal of 21234171657 is 75617143212.

It is an interprime number because it is at equal distance from previous prime (21234171643) and next prime (21234171671).

It is not a de Polignac number, because 21234171657 - 2⁴ = 21234171641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21234171617) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 615769 + ... + 649337.

It is an arithmetic number, because the mean of its divisors is an integer number (954730800).

Almost surely, 2^21234171657 is an apocalyptic number.

It is an amenable number.

21234171657 is a deficient number, since it is larger than the sum of its proper divisors (9317213943).

21234171657 is a wasteful number, since it uses less digits than its factorization.

21234171657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33825.

The product of its digits is 70560, while the sum is 39.

The spelling of 21234171657 in words is "twenty-one billion, two hundred thirty-four million, one hundred seventy-one thousand, six hundred fifty-seven".