21780387453 has 64 divisors (see below), whose sum is σ = 33011712000. Its totient is φ = 12659612160.

The previous prime is 21780387449. The next prime is 21780387457. The reversal of 21780387453 is 35478308712.

It is an interprime number because it is at equal distance from previous prime (21780387449) and next prime (21780387457).

It is not a de Polignac number, because 21780387453 - 2² = 21780387449 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21780387457) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18256225 + ... + 18257417.

It is an arithmetic number, because the mean of its divisors is an integer number (515808000).

Almost surely, 2^21780387453 is an apocalyptic number.

It is an amenable number.

21780387453 is a deficient number, since it is larger than the sum of its proper divisors (11231324547).

21780387453 is a wasteful number, since it uses less digits than its factorization.

21780387453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1482.

The product of its (nonzero) digits is 1128960, while the sum is 48.

The spelling of 21780387453 in words is "twenty-one billion, seven hundred eighty million, three hundred eighty-seven thousand, four hundred fifty-three".