21512157071 has 8 divisors (see below), whose sum is σ = 22466187744. Its totient is φ = 20559686400.

The previous prime is 21512157047. The next prime is 21512157091. The reversal of 21512157071 is 17075121512.

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

It is a cyclic number.

It is not a de Polignac number, because 21512157071 - 2³⁴ = 4332287887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21512157091) 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, 361766 + ... + 417011.

It is an arithmetic number, because the mean of its divisors is an integer number (2808273468).

Almost surely, 2^21512157071 is an apocalyptic number.

21512157071 is a deficient number, since it is larger than the sum of its proper divisors (954030673).

21512157071 is a wasteful number, since it uses less digits than its factorization.

21512157071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 780001.

The product of its (nonzero) digits is 4900, while the sum is 32.

Adding to 21512157071 its reverse (17075121512), we get a palindrome (38587278583).

The spelling of 21512157071 in words is "twenty-one billion, five hundred twelve million, one hundred fifty-seven thousand, seventy-one".