21941780 has 24 divisors (see below), whose sum is σ = 52660608. Its totient is φ = 7522848.

The previous prime is 21941767. The next prime is 21941791. The reversal of 21941780 is 8714912.

It is a congruent 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, 78224 + ... + 78503.

It is an arithmetic number, because the mean of its divisors is an integer number (2194192).

Almost surely, 2^21941780 is an apocalyptic number.

21941780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21941780 is an abundant number, since it is smaller than the sum of its proper divisors (30718828).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21941780 is a wasteful number, since it uses less digits than its factorization.

21941780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 156743 (or 156741 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 32.

The square root of 21941780 is about 4684.2053755146. The cubic root of 21941780 is about 279.9565408741.

The spelling of 21941780 in words is "twenty-one million, nine hundred forty-one thousand, seven hundred eighty".