21953031 has 8 divisors (see below), whose sum is σ = 29303040. Its totient is φ = 14619192.

The previous prime is 21953011. The next prime is 21953033. The reversal of 21953031 is 13035912.

It is a happy number.

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

It is not a de Polignac number, because 21953031 - 2⁹ = 21952519 is a prime.

It is a super-2 number, since 2×21953031² = 963871140173922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21952992 and 21953010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21953033) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 405 + ... + 6638.

It is an arithmetic number, because the mean of its divisors is an integer number (3662880).

Almost surely, 2^21953031 is an apocalyptic number.

21953031 is a deficient number, since it is larger than the sum of its proper divisors (7350009).

21953031 is a wasteful number, since it uses less digits than its factorization.

21953031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8085.

The product of its (nonzero) digits is 810, while the sum is 24.

The square root of 21953031 is about 4685.4061723612. The cubic root of 21953031 is about 280.0043834348.

Adding to 21953031 its reverse (13035912), we get a palindrome (34988943).

The spelling of 21953031 in words is "twenty-one million, nine hundred fifty-three thousand, thirty-one".