21025053428 has 6 divisors (see below), whose sum is σ = 36793843506. Its totient is φ = 10512526712.

The previous prime is 21025053377. The next prime is 21025053479. The reversal of 21025053428 is 82435052012.

It is an interprime number because it is at equal distance from previous prime (21025053377) and next prime (21025053479).

It can be written as a sum of positive squares in only one way, i.e., 11866180624 + 9158872804 = 108932^2 + 95702^2 .

It is a super-3 number, since 3×21025053428³ (a number of 32 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21025053394 and 21025053403.

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, 2628131675 + ... + 2628131682.

It is an arithmetic number, because the mean of its divisors is an integer number (6132307251).

Almost surely, 2^21025053428 is an apocalyptic number.

It is an amenable number.

21025053428 is a deficient number, since it is larger than the sum of its proper divisors (15768790078).

21025053428 is a wasteful number, since it uses less digits than its factorization.

21025053428 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5256263361 (or 5256263359 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 32.

The spelling of 21025053428 in words is "twenty-one billion, twenty-five million, fifty-three thousand, four hundred twenty-eight".