21310155 has 32 divisors (see below), whose sum is σ = 38776320. Its totient is φ = 11098080.

The previous prime is 21310147. The next prime is 21310181. The reversal of 21310155 is 55101312.

It is not a de Polignac number, because 21310155 - 2³ = 21310147 is a prime.

It is a super-2 number, since 2×21310155² = 908245412248050, which contains 22 as substring.

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, 3970 + ... + 7640.

It is an arithmetic number, because the mean of its divisors is an integer number (1211760).

Almost surely, 2^21310155 is an apocalyptic number.

21310155 is a deficient number, since it is larger than the sum of its proper divisors (17466165).

21310155 is a wasteful number, since it uses less digits than its factorization.

21310155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3728 (or 3722 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 18.

The square root of 21310155 is about 4616.2923434289. The cubic root of 21310155 is about 277.2440298494.

Adding to 21310155 its reverse (55101312), we get a palindrome (76411467).

The spelling of 21310155 in words is "twenty-one million, three hundred ten thousand, one hundred fifty-five".