21402251355 has 32 divisors (see below), whose sum is σ = 35367137280. Its totient is φ = 11040416640.

The previous prime is 21402251347. The next prime is 21402251363. The reversal of 21402251355 is 55315220412.

It is an interprime number because it is at equal distance from previous prime (21402251347) and next prime (21402251363).

It is not a de Polignac number, because 21402251355 - 2³ = 21402251347 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 936849 + ... + 959421.

It is an arithmetic number, because the mean of its divisors is an integer number (1105223040).

Almost surely, 2^21402251355 is an apocalyptic number.

21402251355 is a deficient number, since it is larger than the sum of its proper divisors (13964885925).

21402251355 is a wasteful number, since it uses less digits than its factorization.

21402251355 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24651.

The product of its (nonzero) digits is 12000, while the sum is 30.

Adding to 21402251355 its reverse (55315220412), we get a palindrome (76717471767).

The spelling of 21402251355 in words is "twenty-one billion, four hundred two million, two hundred fifty-one thousand, three hundred fifty-five".