21940151 has 2 divisors, whose sum is σ = 21940152. Its totient is φ = 21940150.

The previous prime is 21940111. The next prime is 21940159. The reversal of 21940151 is 15104912.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21940151 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21940159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10970075 + 10970076.

It is an arithmetic number, because the mean of its divisors is an integer number (10970076).

Almost surely, 2^21940151 is an apocalyptic number.

21940151 is a deficient number, since it is larger than the sum of its proper divisors (1).

21940151 is an equidigital number, since it uses as much as digits as its factorization.

21940151 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 21940151 is about 4684.0314900735. The cubic root of 21940151 is about 279.9496125317.

The spelling of 21940151 in words is "twenty-one million, nine hundred forty thousand, one hundred fifty-one".