21002520455 has 16 divisors (see below), whose sum is σ = 28818048000. Its totient is φ = 14394432672.

The previous prime is 21002520379. The next prime is 21002520481. The reversal of 21002520455 is 55402520012.

It is a cyclic number.

It is not a de Polignac number, because 21002520455 - 2¹⁰ = 21002519431 is a prime.

It is a super-2 number, since 2×21002520455² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 81455 + ... + 220544.

It is an arithmetic number, because the mean of its divisors is an integer number (1801128000).

Almost surely, 2^21002520455 is an apocalyptic number.

21002520455 is a deficient number, since it is larger than the sum of its proper divisors (7815527545).

21002520455 is a wasteful number, since it uses less digits than its factorization.

21002520455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303998.

The product of its (nonzero) digits is 4000, while the sum is 26.

The spelling of 21002520455 in words is "twenty-one billion, two million, five hundred twenty thousand, four hundred fifty-five".