21402755 has 8 divisors (see below), whose sum is σ = 28018224. Its totient is φ = 15565600.

The previous prime is 21402739. The next prime is 21402763. The reversal of 21402755 is 55720412.

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

It is not a de Polignac number, because 21402755 - 2⁴ = 21402739 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194516 + ... + 194625.

It is an arithmetic number, because the mean of its divisors is an integer number (3502278).

Almost surely, 2^21402755 is an apocalyptic number.

21402755 is a deficient number, since it is larger than the sum of its proper divisors (6615469).

21402755 is a wasteful number, since it uses less digits than its factorization.

21402755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389157.

The product of its (nonzero) digits is 2800, while the sum is 26.

The square root of 21402755 is about 4626.3111654968. The cubic root of 21402755 is about 277.6450233498.

The spelling of 21402755 in words is "twenty-one million, four hundred two thousand, seven hundred fifty-five".