15821972 has 6 divisors (see below), whose sum is σ = 27688458. Its totient is φ = 7910984.

The previous prime is 15821969. The next prime is 15821987. The reversal of 15821972 is 27912851.

15821972 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 14485636 + 1336336 = 3806^2 + 1156^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1977743 + ... + 1977750.

It is an arithmetic number, because the mean of its divisors is an integer number (4614743).

Almost surely, 2^15821972 is an apocalyptic number.

It is an amenable number.

15821972 is a deficient number, since it is larger than the sum of its proper divisors (11866486).

15821972 is a wasteful number, since it uses less digits than its factorization.

15821972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3955497 (or 3955495 counting only the distinct ones).

The product of its digits is 10080, while the sum is 35.

The square root of 15821972 is about 3977.6842509179. The cubic root of 15821972 is about 251.0461336449.

The spelling of 15821972 in words is "fifteen million, eight hundred twenty-one thousand, nine hundred seventy-two".