21620919 has 16 divisors (see below), whose sum is σ = 30127104. Its totient is φ = 13776000.

The previous prime is 21620903. The next prime is 21620927. The reversal of 21620919 is 91902612.

It is a happy number.

It is not a de Polignac number, because 21620919 - 2⁴ = 21620903 is a prime.

It is a super-2 number, since 2×21620919² = 934928276809122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6319 + ... + 9119.

It is an arithmetic number, because the mean of its divisors is an integer number (1882944).

Almost surely, 2^21620919 is an apocalyptic number.

21620919 is a deficient number, since it is larger than the sum of its proper divisors (8506185).

21620919 is a wasteful number, since it uses less digits than its factorization.

21620919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2918.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 21620919 is about 4649.8299968924. The cubic root of 21620919 is about 278.5852060059.

The spelling of 21620919 in words is "twenty-one million, six hundred twenty thousand, nine hundred nineteen".