21457765426 has 8 divisors (see below), whose sum is σ = 32187306240. Its totient is φ = 10728663348.

The previous prime is 21457765421. The next prime is 21457765531. The reversal of 21457765426 is 62456775412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×21457765426² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21457765426.

It is not an unprimeable number, because it can be changed into a prime (21457765421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74335 + ... + 220093.

It is an arithmetic number, because the mean of its divisors is an integer number (4023413280).

Almost surely, 2^21457765426 is an apocalyptic number.

21457765426 is a deficient number, since it is larger than the sum of its proper divisors (10729540814).

21457765426 is a wasteful number, since it uses less digits than its factorization.

21457765426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219368.

The product of its digits is 2822400, while the sum is 49.

The spelling of 21457765426 in words is "twenty-one billion, four hundred fifty-seven million, seven hundred sixty-five thousand, four hundred twenty-six".