21572451970 has 8 divisors (see below), whose sum is σ = 38830413564. Its totient is φ = 8628980784.

The previous prime is 21572451949. The next prime is 21572451973. The reversal of 21572451970 is 7915427512.

It can be written as a sum of positive squares in 2 ways, for example, as 21392865169 + 179586801 = 146263^2 + 13401^2 .

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

It is not an unprimeable number, because it can be changed into a prime (21572451973) 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, 1078622589 + ... + 1078622608.

Almost surely, 2^21572451970 is an apocalyptic number.

21572451970 is a deficient number, since it is larger than the sum of its proper divisors (17257961594).

21572451970 is a wasteful number, since it uses less digits than its factorization.

21572451970 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2157245204.

The product of its (nonzero) digits is 176400, while the sum is 43.

The spelling of 21572451970 in words is "twenty-one billion, five hundred seventy-two million, four hundred fifty-one thousand, nine hundred seventy".