21290156 has 6 divisors (see below), whose sum is σ = 37257780. Its totient is φ = 10645076.

The previous prime is 21290141. The next prime is 21290161. The reversal of 21290156 is 65109212.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2661266 + ... + 2661273.

It is an arithmetic number, because the mean of its divisors is an integer number (6209630).

Almost surely, 2^21290156 is an apocalyptic number.

It is an amenable number.

21290156 is a deficient number, since it is larger than the sum of its proper divisors (15967624).

21290156 is a wasteful number, since it uses less digits than its factorization.

21290156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5322543 (or 5322541 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 21290156 is about 4614.1257026657. The cubic root of 21290156 is about 277.1572740477.

Adding to 21290156 its reverse (65109212), we get a palindrome (86399368).

The spelling of 21290156 in words is "twenty-one million, two hundred ninety thousand, one hundred fifty-six".