21901316 has 6 divisors (see below), whose sum is σ = 38327310. Its totient is φ = 10950656.

The previous prime is 21901291. The next prime is 21901381. The reversal of 21901316 is 61310912.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 21808900 + 92416 = 4670^2 + 304^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21901291 and 21901300.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2737661 + ... + 2737668.

It is an arithmetic number, because the mean of its divisors is an integer number (6387885).

Almost surely, 2^21901316 is an apocalyptic number.

It is an amenable number.

21901316 is a deficient number, since it is larger than the sum of its proper divisors (16425994).

21901316 is a wasteful number, since it uses less digits than its factorization.

21901316 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5475333 (or 5475331 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 21901316 is about 4679.8841866012. The cubic root of 21901316 is about 279.7843407421.

The spelling of 21901316 in words is "twenty-one million, nine hundred one thousand, three hundred sixteen".