21494778952 has 8 divisors (see below), whose sum is σ = 40302710550. Its totient is φ = 10747389472.

The previous prime is 21494778919. The next prime is 21494778967. The reversal of 21494778952 is 25987749412.

It can be written as a sum of positive squares in only one way, i.e., 21364499556 + 130279396 = 146166^2 + 11414^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1343423677 + ... + 1343423692.

Almost surely, 2^21494778952 is an apocalyptic number.

It is an amenable number.

21494778952 is a deficient number, since it is larger than the sum of its proper divisors (18807931598).

21494778952 is a wasteful number, since it uses less digits than its factorization.

21494778952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2686847375 (or 2686847371 counting only the distinct ones).

The product of its digits is 10160640, while the sum is 58.

The spelling of 21494778952 in words is "twenty-one billion, four hundred ninety-four million, seven hundred seventy-eight thousand, nine hundred fifty-two".